44 THE ENTOMOLOGIST. 



simple hairs, but also and principally with scaly transparent 

 lamellne, more or less rounded or oblong, and traversed by 

 divergent and ramified nervures. These lamellae occupy 

 especially the anterior margin of the head, the first joint of 

 the antennge (which is very stout and protuberant), the outer 

 edge of the tibia3 of the two anterior pairs of legs, and the 

 lateral and posterior margins of the abdomen. Moreover the 

 whole dorsal surface of the latter and of the last thoracic 

 segment is covered with a design having the aspect of a 

 mosaic, composed of hexagonal compartments, and which 

 is not without analogy to the pattern formed by the scaly 

 plates of the carapace of tortoises." " Another remark- 

 able character of these abnormal individuals of Aphis Aceris 

 is the rudimentary state of their generative apparatus. This 

 is reduced to a few groups of small, pale, and scarcely 

 visible cells, none of which arrives at maturity to become 

 transformed into an embryo ; and it retains this character 

 as long as it is possible to observe the animal. The func- 

 tions of nutrition, also, are performed in them in a very 

 unenergetic manner; for from the moment of their birth until 

 that at which we cease to observe them, they increase but 

 little in size, attaining scarcely 1 millimetre. They undergo 

 no change of skin, never acquire wings like the reproductive 

 individuals, and their antennae always retain the five joints 

 which they present in all young Aphides before the first 

 moidt. Nevertheless they possess a well-developed rostrum 

 and an intestinal canal, the peristaltic contractions of which 

 we have distinctly observed." This curious Aphis turns out 

 to be, not, as was at first supposed, the larva of a new species, 

 but a special form of the well-known Aphis Aceris. MM. 

 Balbiani and Signoret consider that they have placed this 

 remarkable fact beyond the possibility of doubt. The 

 question naturally arose. What was the signification " of 

 these abnormal individuals of the Aphis of the maple, and 

 what part did they fulfil in the reproductive functions of the 

 species to which they belong ? They are evidently not males, 

 since their generative apparatus retains the same rudimentary 

 form at whatever epoch we examine them. Moreover, in no 

 known species of Aphis are the males produced at the same 

 time as the viviparous individuals, which are not the true 

 females of the species. There is therefore no other alternative 



