306 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



Ill the noiirse of about three weeks after birth, the larva has attained 

 rather more than double its size at birth, and begins to show some signs of 

 an approaching moult. A considerable quantity of yolk or food globules 

 (adipose tissue) has been accuuiulated, and on each side of the head are 

 seen two setae coiled up spirally as in the embryo before birth, very much 

 as shown in tig. 43. By careful observation the enlarged bases of two 

 setaj can be seen at each side (a, b and a^,b^). lam uncertain whether both 

 pair are coiled in the same direction or in opposite directions, but my 

 impression is liiat the last is correct, and they are so represented in all 

 my drawings. As the old setae (g) are still seen to exist with their con- 

 ical bases {h and i) in their proper position, it seems quite certain that 

 those in the spiral coils are an entirely new set. For a long time I believed 

 that the old setae had been withdrawn into the spirals, and AI. Signoret 

 writes me that such is his opinion.* Dr. E. L. Mark however wrote 

 me, expressing t!ie opinion that they were a new pair, and this 

 caused me to make a rather careful study of the subject with the result 

 that the more I study the matter the more certain 1 am that Dr. Mark is 

 right and a new pair is formed. Among oiher reasons for this belief, in 

 addition to the above statement, is that the setae increase materially in 

 size with each moult, which would be a fact difficult to account for if 

 they "^ were persistent. Tliis spiral formation of the sette just before 

 moulting time, I have observed frequently in this species, and in several 

 species of Aspidiui us and Ftsylla aiid in the last two mentioned genera 

 it is always followed by an actual casting of the skin. It appears prob- 

 able to me that the setae of most if not all Homoptera are formed in the 

 same way. There is one otlier puzzliiig fact in connection with the 

 " moulting'' of this species, notwitiistanding very numerous careful ex- 

 aminations specially directed to this point, I have never under any cir- 

 cumstances succeeded in seeing any tiling in the least resembling a cast 

 off skin. But tlie dilierence in the appearance of the larva before and 

 after is marked and easily recognized at a glance. The only way that I 

 can account for this is that the skin is shed iu small fragments or scales. 

 That something corresponding to a moult takes place at this time, I 

 think there can be no reasonable doubt. 



TUE LARVA OF THE SECOND STAGE. 



After the " Tnoult" above described has taken place the larva, fig. 26, 

 is still twice as long as broad, but nearly equally broad behind as in front 

 of the center, and is no longer broadest in front. The abdomen has 

 grown rather more proportionately than the head and thorax, and the 

 lobes of the seventh segment have iiicreased in size until they meet at 

 the median line, thus forming the so-called '• anal fissure" characteristic 

 of the Lecanites. The marginal spines have become very much more 

 numerous and stouter, there being now upwards of one hundred of these 

 spines nearly equi-distant from one another surrounding the whole mar- 



* Speaking of Fig. 43, Siguoret writes: " Ce n'cst pas, jo crois, nne nouvelle paire de soiee, 

 c'est une ancienne qui se degage d'une espece de tube on gainc qui fonnait lea aucienne« 

 visibles — c'est a vo.r )e formation nouvelle serait asssez ditiicile a expliquer." 



