THE STREPSIPTERA. 
387 
of these minute parasites had already been discovered. One of 
the largest species ( Stylops Spencii) is scarcely more than two 
lines in length, while the smallest species yet known is not more 
than two-thirds of a line, or scarcely a line in breadth with its 
wings expanded. They undergo metamorphosis, and the males, 
when they have become perfect insects, fly and roam about, but 
the females are condemned to a perfectly quiet life. The head 
and the thoracic segments of the bodies of these last are united 
completely, but the abdomen, which is very large, always remains 
very soft, so that the whole of the body only appears to be formed 
Stylops aterrimus. the male. (Natural size and magnified.) 
of two portions. They are ovo-viviparous insects, and the young 
larvae escape as such from the body of the mother. They are active 
creatures, and, being furnished with long legs, crawl over the hairs 
and skin of the hymenopterous insect they are parasitic upon. 
They behave like the larvae of Meloe and Sitaris , whose peculiar 
methods of life have been noticed in our description of the Coleop- 
tera. Clinging on to a wasp or a bee they are carried off and 
finally arrive in the nest or hive, as the case may be, and there 
they attack the larvae. When once fixed upon the hymenopterous 
larvae they undergo a change of skin, and their shape then becomes 
totally different, and their legs are atrophied. But these parasites, 
being exceedingly small, do not kill the larvae ; they suck their 
juices after the manner of the Ichneumons , and do not interfere with 
the metamorphoses of the insects upon which they are parasitic. 
Z 2 
