HO. 1310. NORTH AMERICAN TIIYSANOPTERA— HINDS. 113 



Tubulifera deposit their eggs externally, either singly or in groups, 

 upon leaves and llower.s or under bark, etc., according to their habitat 

 The period of oviposition in all species in this order is quite long. 



^W-— The eggs of Terebrantia are more or less elongated and 

 slightly bean-shaped. They are colorless, delicate in structure, and no 

 micropyle is apparent. The position of the eggs in a thin leaf is easily 

 seen upon holding the leaf before a l)right light, when they appear as 

 brighter spots in the darker green tissue of the leaf. Eggs are laid in 

 almost any green part of the plant, but not in the petals of flowers. 



The eggs of Tubulifera are of an elongate-oval shape, attached with 

 the long axis perpendicular to the surface, and have at the free end a 

 thickening of the chorion with a micropyle in the middle. The eggs 

 vary from 3'ellow to brownish in color. 



Fm7)/-i/oIof/y.— The development of the embryo can be observed in 

 the translucent eggs of Terebrantia. Various writers agree in stating 

 that the germ band is innnersed. Before revolution the appendages of 

 the embryo lie along the convex side of the egg, after revolution along 

 the concave side. The length of the egg stage varies considerably in 

 different species and, even within the same species, according to the 

 weather conditions. So far as life histories are known, this stage 

 appears to last from three to fifteen days in Terebrantia, but no record 

 is found upon this point for the Tubulifera. The pigmented eyes of 

 de^•eloping embryos are particularly prominent. If the egg bed dries 

 the egg is quickly destroyed, but if moist, even though decaying, the 

 j development continues. 



Fnicnjence of the /arm.— When ready to emerge, the young Tere- 

 brantian lan^a breaks through the tender chorion and pu.shes up 

 through the slit in the epidermis made for the insertion of the egg. 

 The larva works its way up till all but the tip of the abdomen is free, 

 but remains supported by the tip in this upright position until the 

 antenna and legs have separated from the body, to which they are at 

 first closely applied, and have become sufficiently dried and hardened 

 ior use. It then falls forward onto its feet and is ready to travel or 

 to feed almost immediately. No observations have been found on this 

 point for the Tubulifera, but just as their eggs are laid singly or in 

 groups, so also do we find the larvte. 



Larval stage.—The length of the larval stage varies with the species, 

 and the statements recorded place it at from five to forty days. 



When just hatched the head of the larva is very large' in proportion 

 to the body and the mouth parts are essentially like those of the adult. 

 The thoracic segments are subequal. The abdomen is strongly con- 

 tracted and very rough. As the larva grows the thorax and abdomen 

 enlarge noticeably, while the head shows little change. In some spe- 

 pies {IIeIiofknj)s) the abdomen becomes strongly distended and shining 

 3.S though under considerable pressure, and a globule of fluid excre- 

 Proc. N. M. vol. xxvi— 02 8 



