424 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



plate extending from the mouth backwards to the posterior limits of 

 the head. The membraneous dorsal wall of the pharynx is raised 

 from the ventral wall of the pharynx by muscles situated in the dorsal 

 region of the head. These induce wave-like motions in the dorsal 

 wall of the pharynx, which suck in and carry the food through the 

 pharynx to the oesophagus. Here it is passed down into the stomach 

 by the contracting action of the walls of the oesophagus. 



The stomach is a blind sac in which the food is, during the early 

 life of this stage, churned or rolled about by the movements of the 

 larva. Later the stomach muscles become developed and constric- 

 tions, which run in waves from one end to the other, roll and turn the 

 food content over and over, thus aiding digestion. 



The posterior portion of the alimentary tract or proctodseum is 

 scarcely developed and there is no external opening, as waste is not 

 passed during this stage. 



The larva at first feeds on the blood and smaller fat globules and 

 avoids the vital parts as the growth of the second stage scale is not 

 arrested until maturity has been reached. At this time usually the 

 first larval stage of the parasite becomes full grown and apparently 

 attacks, during its last days of growth, the vital parts of the scale, 

 thus interfering with its normal functions and preventing the second 

 molt of the scale from taking place. The scale, which previous to 

 this time has been normal in its development, now becomes swollen 

 and distended and at this time begins to turn from its normal lemon 

 yellow to a light orange. The first molt of the parasite usually takes 

 place at approximately the same time that the scale takes on the orange 

 color. 



The molting of this form terminates the first larval stage. 



Second Larval Stage 



This larval form is tail-less and its mandibles are not at first well 

 developed, but soon grow to full size and become chitinized. The 

 head region is indistinct and the body segments are practically indis- 

 tinguishable. 



The tracheal system lies deep within the body and at first contains 

 little or no air, but soon becomes filled and develops rapidly. The 

 first, second and fourth to ninth inclusive short branches of each 

 longitudinal main trunk grow rapidly and terminally at the surface 

 of the body develop spiracles, while the third and tenth branches re- 

 main short and do not develop spiracles. The two main longitudinal 

 trunks are joined posteriorly and anteriorly as in the first larval stage 

 and from these and the bases of the twenty branches are given off 

 numerous branches which ramify to all parts of the body. 



