20 



The Tea insects of India. 



of the Perilampus is an interesting" one, thoug-h the insect has not yet 

 been found in sufficient numbers to be of any practical importance. 



%) ^ 



The wood-cut to the left shows Chalcis euplosa enlarged ; that to 

 the right shows the Perilampus, also enlarged. The natural size in each 

 case is indicated by hair lines. 



The most important parasites are undoubtedly the Tachinid flies, 

 which would seem to act as a most effectual natural check upon the 

 multiplication of this and other defoliating caterpillars in India. Their 

 history requires very careful working out, as there are two forms con- 

 cerned which superficially are almost indistinguishable from each other, 

 though the specialist in Holland, to whom they have been submitted, 

 looks upon them as representing separate species. The point is an im- 

 portant one to investigate, as one of the two species [vis., Trycolyga 

 lombycis, Becher) is the well-known silk-worm fly which is very destruc- 

 tive to silk-worms in Murshedabad and elsewhere in Bengal. 



The figure above shows Trycolyga h^mlycis on three stages of develop- 

 ment, all natural size. To the left is the full-grown larva (maggot), in 

 the middle is the pupal ease, and to the right is the sexually mature fly. 

 The habits of Trycolyga homhycis, as observed in the silk districts,^ are 

 briefly as follows : — The fly lays its eggs, one at a time, on the bodies of 

 the caterpillars. One fly is therefore able to infect a large number of 

 caterpillars. The eg^ hatches a few hours after it is laid, and out of it 

 creeps a tiny maggot which bores its way into the body of the cater- 

 pillar. Here it lives and grows, feeding on the fatty tissues of its host 



^ See Indian Museum Notes, Vol. T, p. 83. 



