276 fnsecta. 



L'auteur etudie les caracteres morphologiques de deux microfilaires ä gaine 

 parasites chez des tirailleurs senegalais d'Algerie. Sur des frottis colores au Gieuisa 

 on distüigue conmie il suit le Mf. bancrofri du Mf. diurna. La gaine de Mf. ban- 

 crofti est fortement coloree, les noyaux se colorent en beau bleu, les noyaux de 

 l'extremite cephalique se montrent brusquement termines en rangee droite, les 

 noyaux du corps sont plus petits, plus arrondis, moins serres que dans l'autre 

 espece; les noyaux de l'extremite caudale n'atteignent pas la pointe, enfin le corps 

 central est bien colore. Au contraire chez Mf. diurna la gaine reste incolore; les 

 noyaux se colorent en bleu violace, ceux de l'extremite cephalique sont plus ou 

 moins irregulierement dissemines, les noyaux du corps sont plus gros, plus serres, 

 moins reguliere que dans l'autre espece; les noyaux occupent toute la longueur 

 de l'extremite caudale, enfin le corps central n'apparait pas. Moreau. 



Insecta. 



833) Sllliel, A. F., Biology of the Thysanoptera I. Factors govern- 

 ing local distribution. In: Amer. Naturalist, Bd. 48, Heft 3, S. 161 — 176 

 u. 236—247, 1914. 



The paper deals with the ecology of the Thysanoptera or thrips. Experi- 

 ments are described on the behaviour in relation to light and gravity. The 

 origin of the various responses is unknown. Some are supposed to be adoptive, 

 but none purposeful. 



The second part of the paper deals with sex and the life cycle. In some 

 species both sexes pass through the winter, in others the males perish. In Eu- 

 tlirips tritici there was no indication of an alternating life cycle. In another 

 species the two sexes appeared at different seasons, and in a third Authoihrips 

 verbasci there was an increase in males in the late summer. 



A preliminary cytological examination showed a lagging chromosome in 

 the spermatocyte divisions, but the study is not yet complete. Gates. 



834) Greene, C. T. ? The Cambium Miner in River Birch. In: Jour. Agr. 

 Research, Vol. Nr. 6, S. 471—474, 1914. 



It is decided that Agromyza pruinosa is at least one of the insects, and pos- 

 sibly the only one, that produces the pithray flecks in birch in America. The 

 trees attacked are apparently healthy and infested ones cannot be detected by 

 their outward appearance, but only by removing the bark and exposing the cam- 

 bium. The life history of Agromyza pruinosa is given. Pearl. 



835) Braun, A. F., Evolution of the Color Pattern in the Microlepi- 

 dopterous Genus Lithocolletis. In: Journ. Nat. Sei. of Phila., Vol. XVI, See. 

 Ser. S. 105—168, 1914. 



Observations on the development of color in the pupal wings and a com- 

 parison of the color pattern in adult forms of Lithocolletis show that in this group 

 the primitive color pattern is a serie of seven uniformily colored pale, yellow 

 transverse bands, separated from one another by unpigmented areas. The dis- 

 posal of these bands is dependent upon the course of the longitudinal nervures, 

 since the points of origin or the tips of the veins mark the positions of the un- 

 pigmented fasciae between the bands. From this primitive color pattern, the se- 

 veral different types of color pattern in this genus are held to have been derived. 

 Evolution has taken place, aecording to the author, in definite directions, under 

 the action of three general processes, which were found to be sufficient to ex- 



