520 HOMES WITHOUT HANDS. 



is obtained the opium of commerce, is attacked by a species of 

 gall-fly, which lays its eggs in the large head, or pod, and some- 

 times does much damage to the plant, the delicate divisions be- 

 tween the seed-vessels being rendered quite hard and solid, and 

 the pod itself deformed. Mr. Westwood has described a species 

 of gall-fly which infests the turnips, and another species is known 

 to lay its eggs upon wheat. 



As if to show that the family of Cynipidae is really related to 

 the ichneumons, it has been discovered that some species of this 

 family are actually parasitic upon other insects. In treating of 

 this remarkable fact, Mr. Westwood writes as follows: "The re- 

 lations of these insects with the following families (i. e., Evanida? 

 and Ichneumonidte) have been already noticed. It had always 

 appeared to me contrary to nature that a tribe of vegetable-feed- 

 ing insects should be arranged in the midst of parasites ; nor was 

 it until I had an opportunity of ascertaining the parasitic habits 

 of some of the species of the family that I was enabled to form a 

 just notion as to the true value of the parasitic or herbivorous 

 nature of these insects. In June, 1833, 1 detected a minute spe- 

 cies, Allotria victrix, in the act of ovipositing in the body of a rose 

 aphis, and I subsequently succeeded in hatching specimens of the 

 perfect insect from infested aphides." 



A figure of the tiny insect is given, as it appeared while in the 

 act of depositing its eggs, and has a rather remarkable effect from 

 the fact that the very minute dimensions of the parasite make 

 the aphis look quite a large insect. Other species of this family 

 are also known to be parasites. The rose aphis is certainly infest- 

 ed by two species of gall-fly, and probably more, while the aphides 

 which are found on the willow, the cow-parsnip, and other plants, 

 also fall victims to the Cynipidse. There is one genus of this 

 family, called Figiies, which is parasitic on the larva or pupa of 

 certain dipterous insects. 



The Cynipidae are not the only insects that produce galls 

 upon different plants. For example, several species of beetle are 

 known to pass their earlier stages in swellings produced by the 

 puncture of the parent insect. There is a little weevil of a gray- 

 ish-brown, which is mentioned by Mr. Eennie as forming a gall 

 upon the hawthorn. 



" In May, 1829, we found on a hawthorn at Lee, in Kent, the 

 leaves at the extremity of a branch neatly folded up in a bundle, 



