Four species are recognized in the genus Holcopsis Enderlein: bifenestrata (Osten Sacken 1886), fenestrata Enderlein 1923, bequaerti (Philip 1943) and pilifera (Philip 1943). All specimens for which the locality is known are from the State of Durango, Mexico. The genus is characterized and its possible relationship with Bolbodimyia Bigot is indicated. Collection data for all known specimens are given. The species are characterized by the use of a descriptive key. The wing, third antennal segment, and second palpal segment of the female of each species is illustrated.

Cattle grubs, first-instar larvae of Hypoderma bovis (L.), were removed from nine slaughtered heifers. Two of these heifers had previously been treated with coumaphos, three with Ruelene, and two with trichlorfon. The remaining two heifers were not treated with insecticides and served as sources of control grubs. The grubs, after removal from the hosts and fixation in formalin, were incubated with one of the two cholinesterase substrates, acetylthiocholine iodide or 5-bromoindoxyl acetate. Cholinesterase was completely inhibited in the central nervous systems of the grubs whose hosts were treated with Ruelene. This inhibition was also virtually complete in grubs from heifers treated with trichlorfon and was usually complete in those from the heifers treated with coumaphos. This is presented as histochemical evidence that the three systemic insecticides inhibit the cholinergic enzymes in the grubs, thus causing them to die while still in the body of the host.

Depuis la découverte du pouvoir insecticide du DDT, des recherches intensives ont été faites sur d'autres composés synthétisés à partir de la charpente squelettique du DDT, à savoir le 1,1-diphényléthane:

De ces composés analogues au DDT, certains montrent une valeur insecticide supérieure à celle du DDT; d'autres s'avèrent inférieurs. du moins dans les conditions expérimentales que nous avons choisies. Nous présentons ici les résultats que nous avons obtenus dans nos expériences sur la toxicologie du dérivé cyanuré du DDT. Ce composé a été synthétisé pour la première fois par Perron (4,5) à l'Institut de Chimie de l'Université de Montréal. Nous avons utilisé la méthode mise au point par cet auteur pour préparer les quantités dont nous avions besoin pour notre travail.

An investigation was made of the impact of a series of environmental catastrophes upon herbivore population regulation through density-dependent genetic feedback interactions with simulated plants. Mean density and amplitude of fluctuation of the herbivore in the control system (only susceptible alleles in the plant population) were higher than in the genetic feedback system (3 resistant alleles and 3 susceptible alleles in the plant population). Mean density and amplitude of fluctuation of the herbivores in the catastrophic system (only susceptible alleles in the plant population and the herbivore population subject to a series of environmental catastrophes) were lower than in the control and genetic feedback systems, but both mean density and amplitude of fluctuation were higher than in the genetic feedback and catastrophic system (3 resistant and 3 susceptible alleles in the plant population and the herbivore population subject to a series of environmental catastrophes). The results of this experiment suggest that genetic feedback can exert a controlling influence in population dynamics even in systems where environmental catastrophes are a common occurrence.

I wish to correct a few mistakes which I have made in the paper on this subject, which was published in the Entomologist Vol. II., No. 2.

1st. I have said that “not a single American species of Hemiteles, so far as I am aware, has as yet been described under that generic name as occurring north of the West India Islands.” This is incorrect. Mr. Riley, in his Missouri Report, has described two species, viz., H. thyridopteryx♂ ♀ , and H. Cressonii ♂, as found in his State

Anterior wings rich chocolate - brown with creamy white stripes or markings. Costal margin lighter brown. A broad line running from the base of the median vein nearly to the posterior angle, where it becomes slightly forked; from this proceeds a slightly curved narrower branch, from the centre of the wing nearly to the costal edge, and one-third the distance from the apex ; a zigzag mark composed of three straight lines, the first being the broadest, and the third one-half the length of the others, proceeds from the outer angle, where it joins the first line, and terminates under the costal edge; the whole forming a distinct W crossed at the top by the transverse band. Inner edge faintly marked with creamy white.

Head, palpi and thorax clothed with rough olive-ochreous hair, the palpi with a considerable admixture of black hairs apically. Pectus and legs with similarly colored, rough vestiture. Abdomen dorsally with sparse ochreous hairs over a black ground and with the posterior margins of segments ringed narrowly with ochreous scales ; laterally and ventrally with strong vestiture of rather bright yellow hair. Primaries deep pink with a broad, subterminal curved band of oliveochreous from below apex of wing to near base of wing above vein I, narrowing considerably at this point; a streak of the same color in the cell.

Retinia Austriana, n. sp.—The Austrian Pine (Pinus laricio Austriaca) in the vicinity of Toronto is badly infested by the larveæ of a moth which is apparently an undescribed species of the genus Retinia. It resembles in certain particlars the form Retinia Comstockiana. This species was described in the Canadian Entomologist of Aug., 1879, by Prof. C. H. Fernald State College, Orono, Me. The specimens, however, were obtained at Ithaca, N.Y. Where they were found boring in the small branches of Pinus rigida.

In September, 1873, Mr. T. L. Mead, who was then at Coalburgh, observed a ♀ pseudargiolus depositing eggs upon the flowers of Actinomeris squarrosa, and on examining the flower heads found a number of eggs. He brought home two of the females, and enclosed them in a muslin bag upon the flower heads of the same plant, near my house, the plant being not at all an uncommon one here. Several eggs were soon deposited, and in due time the larvae were hatched and some of them were carried through to chrysalids, a change which occurred about the middle of October.

In the first week of July my attention was drawn by my friend, Mr. Joshua Thomson, of Levis, to a strange sight, The plum trees in his grounds were infested with myriads of a new species of Torymus, as many as thirty of the insects appearing on one plum. I never witnessed anything in my entomological pursuits more remarkable. The brilliant little creatures could be seen in the act of depositing their eggs; their ovipositors thrust deep into the fruit. Some of the plums attacked showed signs of a previous attack of the Curculio, but most of them did not. Whether the larvæ of the species feed on the flesh and juices of the plum or attack the grubs of the Curcuiio, I cannot say, for I was unable to follow the life-history of the species.

Of the many species of fleas incriminated in plague transmission, the most notorious is the oriental rat flea, Xenopsylla cheopis (Rothsch.). This is due to its early discovery as a plague vector (Simond, 1898), its demonstrated superior ability to transmit the infection (Kartman and Prince, 1956), and its recognition as the principal vector of plague from rat to man. Holland (1949) regards its presence in any geographical area as a matter of concern.

Allied to precationis and ,gamma. It differs by the distinct yellow shaded geminate t. p. line having but a single acute tooth at vein 2 ; the line running more outwardly at this point, and being othewise even throughout. Also by the shape of the metallic spot ; this is open, silver bordered, running outwardly obliquely from the median vein to the t. p. line at vein 2, sub-triangulate, the bordering lines fusing outwardly to a point, forming an oblique uneven V. The median space below and beyond the metallic mark is shaded longitudinally with obscure chalceous.

There being no published list of the American species of Thysanoura, I have thought it advisable to bring my notes together in a connected form. The names adopted are based on a careful study of many specimens from all parts of the country, and the arrangement of families and genera is a combination of that of Tullberg, Lubbock, and Comstock. I have preceded the catalogue by a list of the more important papers containing descriptions of American species, and I have followed the names of all those species known to me by an exclamation point.

Optical brighteners were recently discovered to function as UV protectants for baculoviruses of insects (Shapiro 1992) and, also, to enhance entomopathogenic activity of these viruses (Hamm and Shapiro 1992; Li and Otvos 1999a). Enhancement of viral activity by brighteners varied greatly from one virus–host system to another: for example, from 1500-fold in LdMNPV against Lymantria dispar (L.) (Lepidoptera: Lymantriidae) (Argauer and Shapiro 1997) to 2- to 13-fold in a multicapsid nuclear polyhedrosis virus of Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) (CfMNPV) against Choristoneura occidentalis Freeman (Li and Otvos 1999a). The reason for this variation in enhancement of viral activity is still unknown. In this study, we used CfMNPV to compare the levels of viral enhancement by an optical brightener between C. occidentalis and C. fumiferana.