140 STREPSIPTERA. 



Wasps, usually exhibiting a preference for the solitary Bees of 

 the family ANDRENIDJE. The name of the group, which means 

 "twisted wings," has reference to certain curious appendages, 

 which are seen in front of the wings ; these appendages are at- 

 tached to the second segment of the thorax, whilst the wings (of 

 which there is only one pair) proceed from the third ; hence the 

 former are to be regarded as the altered rudiments of the ante- 

 rior pair of wings. The organs of the mouth are reduced to a 

 very rudimentary condition ; the eyes are large and prominent, 

 being mounted on footstalks, as in many Crustacea. The anten- 

 nae are of singular form, being usually furnished with an internal 

 branch or projection, nearly as long as the antenna itself. The 

 wings are large, and folded in a fan -like manner ; when in 

 motion, they make a buzzing sound, which is considerable in 

 proportion to the size of the animal. The third segment of the 

 thorax, to which they are attached, is developed to an extraordi- 

 nary size in proportion to the rest of the animal, and the abdomen 

 is very small. These are the characters presented by the male, 

 the only sex which was correctly known until very recently ; and 

 it was not until the discovery of the mode of life of these curious 

 creatures, and thus of the true female, that their proper place in 

 the system of Entomology could be determined. 



723. The phenomena of their existence are very singular. 

 Their larvae are parasitic upon those of different species of Bees 

 and Wasps ; they are footless maggots, with no trace of external 

 organs of any kind. When full grown, the head becomes horny, 

 and it is then pushed out between the segments of the abdomen 

 of the Bee or Wasp, which, by this time, is approaching the 

 perfect state. This is the only change that takes place in the 

 females, which remain in the form of maggots within the body 

 of their victim, with only their heads protruded ; and from this 

 circumstance they were, until very recently, taken for the larvae. 

 With the males, however, the case is widely different. They 

 become converted into inactive pupae, in the interior of the larva- 

 skin, which still remains within the abdomen of the Bee, and 

 finally emerge from their living prison, by pushing off the small 

 horny cap which protrudes between the segments of its body. 



