ENEMIES OF APHIDES, 261 



The most characteristic details shown in these figures will 

 enable the reader to appreciate the main features of difference 

 between this genus and those already described and figured without 

 the wearisome repetition of detailed description. The colouring 

 is always more or less dull, and partakes of yellow, brown, and 

 black, and the general aspect of the insects, especially as to the 

 head, is somewhat long and pointed in comparison with Capsus, 

 and, though not so narrowed as Plagionathus, the head of the 

 latter is much more obtuse. 



To facilitate the recognition of other species of the genus as 

 aphis eaters I have drawn also on Plate XIII., figures of ^. nemo- 

 ralis, A. gallarum ulmi, and A. visci. 



The development of the Hemiptera-Heteroptera is still very 

 obscure, and, in view of the difficulties in the way of investigation, 

 nothing short of an exhaustive study of the whole subject with the 

 advantages of a suitable insectary and other conveniences will 

 avail to put us in possession of the consecutive phases of these 

 insects' history. I myself have made many attempts during the 

 past two years to observe the development, but have been met by 

 great difficulty in obtaining eggs which had any reasonable cer- 

 tainty of being those of the insects in question. The ordinary 

 sources of supply appear unable to provide eggs of plant bugs, and 

 they seem to be very rarely observed on vegetation, while I have 

 never known the female produce eggs in confinement. 



So far as I can judge from fragmentary observation, the eggs 

 are laid about the middle of spring, and it is some weeks fre- 

 quently before the young are hatched. The eggs are elongated, 

 and are attached usually to vegetation in layers or groups, the 

 upper or free end having some sort of ridges or spines around it, 

 and the colouring varying from quite pale to a deep brown. The 

 young, on leaving the egg, shows little of its ultimate shape, this 

 only developing when the first moult takes place, which is some 

 fourteen or fifteen days after its emergence from the egg, and 

 seems to depend upon the supply of food. Meanwhile, a small 

 oblong insect, considerably wanting in development, except as to 

 its rostrum, is the larval representative of the future Hemjpteron. 

 After the skin is first cast, some of the recognised characters of 

 the sub-order become apparent, and it is in some cases possible 



