XVII] 



BIONOMICS. ETC. 



331 



of the Dragonfly's egg, which it devours completely in a few 

 days. It then pupates, and emerges as an imago ten or twelve 

 days later. The female uses her wings for swimming, and by 

 this means seeks out the eggs of Calopteryx, which are laid in the 

 leaves of water-lilies [94]. 



I have found the epithelium of the mid-gut in the larva of 

 Ischnura heterosticta almost completely destroyed by a large 

 undescribed species of Gregarine Sporozoan (fig. 169), four or five 

 of which completely filled the lumen of the gut. The larva can 

 live for days with this parasite inside it, but gradually becomes 

 weak and sickly-looking, owing to its inability to digest any food. 



Fig. 168. Polynema nataris Lubbock, 

 ?, Britain ( x 20). After Miall, from 

 Lubbock. 



Fig. 169. T.S. through mid-gut of larva 

 of Ischnura heterosticta Burm., con- 

 taining several large Gregarinida (g) 

 affixed to its wall ( x 75). Original. 



De Selys found a large Filaria in the abdomen of Sympetntm 

 ftaveolum. 



The imagines do not, however, appear to suffer much from true 

 parasites. Dragonflies whose larvae live in still water (Libettnlinae, 

 Agrioninae) are frequently found covered with a species of small 

 red mite (family Hydrachnidae). These are false parasites, usually 

 found clinging to the underside of the thorax, the bases of the 

 wings, abdomen and legs of males and females alike. All the 

 mites on the Dragonfly are young ones. I have recently succeeded 

 in finding the mature female of this species, which is a rather 

 large animal (3-4 mm. diameter) of a brilliant carmine colour. 



