CADDIS FLY. 167 



three following orders need little more than just men- 

 tion of their names. 



These are the order Neuroptera, in which are in- 

 cluded the Dragon-flies, May-flies, and others, amongst 

 which are several kinds of great service in destroying 

 Aphides. For figure of one species, see that of 

 Chrysopa j)erla, or Golden-eye, p. 34. 



The order of Strepsiptera, or '' Bee Parasites," is 

 almost microscopic, and is distinguished by the fore 

 pair of wings being merely represented by twisted 

 appendages. 



The order of Trichoptera, or Caddis-flies, spend 

 their maggot-life commonly in cases formed of shells, 



Fig. 131.— Caddis Fly. 



or bits of stick, or little stones, or, in fact, of any- 

 thing available, which they can spin together, in our 

 ponds or streams. 



The student will observe that the five orders, which 

 we have considered at some length, have one great 

 point in common : they are all quite different in the 

 first state (as grubs) to what they are in the second 

 (as chrysalids), and to what they are as perfect 

 insects ; also that in the chrysalis state, even if the 

 limbs are visible, still they are not able to use them ; 

 and thus we have one clear season for measures of 

 prevention, which it is well to make the most of. 



Further, that each one of these orders — the Flies, 



