108 



INSECTS AFFECTING THE ORANGE. 



composed of two closely- applied lobes. The upper surface at its widest 

 part is marked on each side with shallow depressions, which are faintly 

 prolonged on the sides and reach nearly to the terminal lobes. The 

 abdomen consists of about, thirty segments. The beak, a short, curved 

 tube, is usually retracted between the organs of the mouth. The latter 



form a truncated cone, concealed from 

 above by the projection of the front, 

 and difficult to resolve into its compo- 

 nent parts. Under high powers it can 

 be seen to consist of at least two thick 

 lobes, which in the living Mite have a 

 reciprocal forward and back movement. 

 The two pairs of legs are placed close 

 together, at or very near the anterior 

 extremity, and project forwards. They 

 are four-jointed, and terminate in a 

 curved spine, with opposing bristles. 

 (Fig. 45, c.) The intermediate joints 

 bear one or two very long, curved bris- 

 tles. Several fine bristle-hairs, arising 

 from the under surface of the body, 

 curve upwards at the sides, and two 

 very long bristles at the caudal extrem- 

 ity, curving downwards, are trailed 

 after the Mite as it crawls. 

 The length of the adult Mite is 0.14 rnra (y^ inch). The young do not 

 differ essentially in structure from the adults, but are thick and. short, 

 almost cordiform, and the legs are very short. 



The eggs, which are deposited singly or in little clusters upon the 

 surface of the leaves, are spherical, transparent, with a yellow tinge. 

 Their diameter is more than half that of the mother at its widest part, 

 aud they probably increase in size by the absorption of moisture after 

 they are laid ; otherwise the body of the Mite could not contain more 

 than three or four fully- developed ova. The embryo is curved within 

 the egg, its head slightly overlapping the tail. (Fig. 45, d.) 



Life-history. In hot weather the eggs hatch in four or five days, but 

 in winter their development is more or less retarded by cold, although 

 it is not entirely arrested even by frost, and the duration of the egg 

 period seldom exceeds two weeks. 



The young are bright, translucent yellow in color. Within a week 

 or ten days they undergo a metamorphosis or molt, during which the 

 animal remains dormant for about forty-eight hours. With its legs, 

 which are placed close together, and stretched out in line with the, 

 body, and with its two-lobed anal proleg, it clings closely to the surface 

 of the leaf. The form becomes more elongate and spindle-shaped. The 

 body of the transforming Mite separates from the old skin, which be- 



Fio. 45. The Orange Rust-mite: a, dorsal 

 view ; ft, lateral view enlarged, the dot 

 in circle indicating natural size; c, leg; 

 d, egg, with embryo just about to hatch- 

 more enlarged. ( After Hubbard.) 



