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TEXT-BOOK OF ENTOMOLOGY 



in the skin of the caterpillar destined to serve as the host of the parasite, the 

 eggs, as stated by De Geer, being retained more firmly in the integument by 



the stalk so swelling as to form two 

 knobs (Fig. 498, c). 



Certain Homoptera also have stalked 

 eggs, as those of Psylla pyricola (Fig. 

 489, B), those of Aleyrodes citri (C, 

 a, ft), and of an allied form, Aleuro- 

 dicus cocois (Z)), and those of Corixa 



FIG. 488. Young larva of Paulsons in posi- 

 tion of feeding on the skin of a caterpillar : a, the 

 egg-shell. After Newport, from Sharp. 



(Fig. 493). 



Reference should also be made to 



the eggs of lice, which are oval and 

 attached to the hairs of their host. Those of the ox bot-fly (Hypoderma lineata) 

 are usually placed four to six together, and fastened to a hair. The lower portion 

 of the egg is admirably 



adapted for clasping a A E 



hair. "It consists of - cy"~~\ J n f 



two lobes, forming a 

 bulbous enlargement, 

 which is attached to 

 the egg by a broad, but 

 rather thin, neck, so 

 that, when the latter is 

 viewed sidewise, it ap- 



pears as a slender pedi- ^ ^ _ 8talked ^ . ' Chalcid (after pabre) 



eel" (tig. 490, a-O). B, of Psylla (after Slingerland) ; C, of Aleyrodes; D, of 

 (Rilev in Insect Life Aleurodicus (after Eiley and Howard); E, of Dryuphanta 

 > > ' '' scutftlaria (after Adler). 



iv, p. 307.) The egg of 



another fly (Drosophila ampelophila, Fig. 491) bears a pair of long, slender ap- 

 pendages near the anterior end. "The egg is inserted into the soft pulp of the 

 decaying fruit ; these appendages leave the ovipositor last, and are spread out upon 



the surface of the mass. They, in this way, 

 serve to keep the egg in place, and thus insure 

 the emergence of the larva into the open air 

 instead of into the more or less fluid mass in 

 which the egg is situated. The larva issues 

 from the egg just above the base of these ap- 

 pendages." (Comstock.) 



Mode of deposition. 

 The exact process 

 of oviposition has 

 been rarely ob- 

 served, or at least 

 not observed in de- 



FIG. 491. Ega of Dro- 

 sophila. After Comstock. 



FIG. 490. Eggs of ox bot-fly, enlarged. After Riley. 



