196 



INSECT CALENDAR. 



month, is the Rose Saw fly (Selandria rosse, Fig. 236) aud S. 

 cerasi. The eggs are then laid, and tlie last of June, or early in 

 July, the slug-like larvas mature, and^ 

 le perfect insects fly in July. Various 

 all flies now lay their eggs in the 

 1 ads, leaves and stems of various kinds 

 f oaks, blackberries, blueberries and 

 ther plants. 



Dipterous Gall flics, are now laying 

 heir eggs in cereals. The Hessian 

 ly (Cecidomyia destructor) has two 

 1 roods, the fly appearing both in 

 pring and autumn. The fly lays 

 iventy or thirty eggs in a crease iu 

 he leaf of the young plant. In about 

 lour days, in warm weather, they 

 hatch, and the pale-red larvae "crawl 

 down the leaf, work- 

 ing their way in be- 

 tween it and the main 

 stalk, passing down- 

 ward till they come 

 to a joint, just above 

 which they remain, a 

 little below the sur- 

 face of the ground, 

 with the head tow- 

 ards the root of the 

 plant. Here they imbibe the sap by suction 

 aloi>e, and, by the simple pressure of their 

 bodies become imbedded in the side of the 

 stem. Two or three larvse thus imbedded 

 serve to weaken the plant and cause it to wither 

 and die. The second brood of larvae remains 

 through the winter in the flax-seed, or pupa- 

 rium. By turning the stubble with the plough 

 in the autumn and early spring, its imago may 

 be destroyed, and thus its ravages may be 

 checked. (Figure 237 represents the female, 

 which is about one-third as large as a mosquito 

 b, the pupa; and c represents the- joint near the 



Water Flea. 



Selandria rosae. 



a, the larva; 

 rrouud where 



