[13] 



COLLECTING AND PRESERVING INSECTS RILEY. 



form of the order, including all the social and fossorial vspecies. The 

 insects of this section must be considered essentially beneficial to man, 



FiGt. 7. — A Horn-tail, Tremex colionba. o, lar\-a, showing Tbalessa larva attached to its side; &, 

 head of larva, front view, enlarged; c, female pupa, ventral view; d, male pupa, ventral view; e, adult 

 female— all slightly enlarged. 



notwithstanding the occasional sting of a bee or wasp, the boring of 

 a carpenter bee, or the imj^ortunities of the omnipresent ant. Not only 

 do tliey furnish us with honey and wax, but they play so imj^ortant a 

 part in the destruction of insects injurious to vegetation that they 

 may be loolted upon as God-appointed guards over the vegetal king- 

 dom — carrying the i)ollen from plant to i)lant, and insuring the fertiliza- 

 tion of di(Ecious species, and the cross-fertilization of others; and being 

 ever ready to clear them of herbivorous worms which gnaw and destroy. 

 The whole section is well characterized by the uniformly maggot-like 

 nature of the larva. The transformations are complete, but the chitin- 

 ous larval covering is often so very thin and delicate that the budding 

 of the members, or gradual growth of the pupa underneath, is quite 

 plainly visible, and the vskin often peels off in delicate flakes, so that 

 the transition from larva to j)uj)a is not so marked and sudden as in 

 those insects which have thicker skins. 



"The terebrantine Hymenoptera, or Piercers, are again divisible into 

 two subsections : first, the Entomophaga, which are, likewise, with the 

 exception of a few gall-makers, beneficial to man, and include the 

 parasitic families, and the gall-flies; second, the Phytophaga, com- 

 prising the Horn-tails (Uroceridw), and the Saw-flies {Tenthredinidw)^ 



