CHAPTER V 



THE GROWTH AND TRANSFORMATIONS OF INSECTS 



Stories of the lives of insects, or their "life histories," are 

 among the most interesting and marvelous to be found in the 

 realm of science, furnishing themes for poet, philosopher, and 

 scientist. 



Egg. All begin life in the egg stage. The shape, size, number, 

 and position of the eggs are as different as are the many families 

 of insects, and cannot be described in general terms. Usually they 



^5^,0 O D 



m n o p q r s 



FIG. 55. Eggs of different insects. (Enlarged) 



a, Tortrix ; 6, Liparis ; c, a Noctuid ; d, usual shape of those of a bark borer ; *>, May-beetle 

 (Lachnosterna) ; /, midge (Chironomus) ; ", Lyda ; //, fly (Mused) ; /', honey-bee ; k, gall-fly 

 (Rhodites rosae) ; /, lace-winged fly (Chrysopd) ; m, pomace-fly (Drosophild) ; >z, Pentatoma; 

 o, back-swimmer (Nepd) ; /, butterfly (Pieris crataegi) q, bedbug ; r, louse, fastened to a 

 hair; s, bot-fly (Hypoderma). (After Judeich and Nitsche, from Packard) 



are laid upon the food plant, or host, but occasionally their position 

 could not be accounted for were the habits of the young not known. 

 The I- umber laid by a female may vary from one or two, as in the 

 case of some aphides, to many thousands, as in bees and termites, 

 but a fair average would probably be about one hundred. The size 

 varies inversely with the number produced, and the shape and struc- 

 ture are largely influenced by the environment in which the eggs are 

 laid. In a few cases the eggs hatch within the body of the female, 

 which thus gives birth to live young, as do the aphides. Those 

 eggs which hatch during the summer have an incubation period of 

 from a day or two, as do those of certain flies and mosquitoes, to 



45 



