408 



tNSECTS AP.K'OAD. 



without the aid of a tolerably powerful magnifying-glass. The 

 body of an ordinary specimen is very much the same size as the 

 letter i; and if an o be placed at either side of the i, they will 

 be about as large as the wings. The generic name of Sclero- 

 derma is formed from two Greek words signifying "hard- 

 skinned/' and is given to these insects on account of the hard- 

 ness of the integuments. 



The species which is here represented is one of a large and 

 very interesting group of insects. There are many of them, 

 and this particular species has been selected because it is one 

 of the largest, of the group. As a rule they are very small, 



Fig. 203. — Leucospia Aruera. 



(Black, with yellow marks.) 



and the insects of this genus are absolute giants among pigmies 

 when compared with their relatives. 



Their habits are rather remarkable. They are parasitic upon 

 various Hymenoptera, especially upon the Mason Bees. The mode 

 in which the female deposits her eggs Ls very curious. The ovi- 

 positor is very Long, and when at rest is turned over the back, its 

 point passing over the thorax of the insect. On account of this 

 structure it was thought by some entomologists that the Leu- 

 cospis was obliged to attack its victim from behind. According, 

 however, to an account given to Mr. West wood by an eye- 

 witness, this is not the case, and the insect proceeds as follows: — 



Mason Bees always choose for their building-place a hole in 

 an old wall. In this hole they deposil an egg. together with 

 u supply of food for the young larva, and then close it up. 



