:]'24 



Hdhlts of the (rretnlKHixc W/rifc Fh/ 



the stylets. The rostrum may be drawn into the head to such a great 

 extent that the dorsal end of the groove nearly reaches the dorsal 

 wall. It may also be invaginated upon itself like a glove finger (Fig. 46). 

 These arrangements are for the insertion of the stylets, insomuch as the 

 rostrum is longer than the stylets. The portion of stylets outside the 

 plant is completely enclosed in the groove. Hence the rostrum function- 

 ally shortens as the stylets are inserted. There is no arrangement in 

 the head for the retraction or expulsion of the stylets themselves. When 

 the insect is not feeding, the stylets are completely enclosed in the 

 rostral groove. 



Eyes (Fig. 48). The eyes of the adult are compound, and each 

 is divided externally by an area covered with short hairs, into lower and 



Fig. 48. Eye.s. 



Fig. 49. Side view of head. 



upper portions, the upper having smaller facets than the lower. They 

 are very large, and just above each is an ocellus (Fig. 49). The two 

 parts of each eye unite inside the head. 



Mouth-parts. The mouth-parts have the same general structure 

 as in the preceding stages, but there is one great difference. In the 

 larvae the stylets may be withdrawn inside the body (Fig. 50), probably 

 into a pouch as in Monophlebus (Coccidae). The mandibles, are not 

 fused, either with themselves or with the maxillae, and they may slide 

 upon the latter. They are very slender structures without teeth or 

 serrations. 



Segmentation (Figs. 38 and 40). The attachment of the abdomen 

 to the thorax is very narrow. From the dorsal surface small protho- 

 racic and large meso- and meta-thoracic segments are visible. Behind 



