The B.ology of Maine Species of Altica. 159 



tubercles v and vi, and vii and viii ; vii and viii are fused into a single 

 tubercle, the large lateral tubercle, bearing two setae ; tubercles ix and x 

 are fused into a single tubercle, bearing two setae ; tubercle xi is want- 

 ing ; tubercle xiii in each case is fused with its fellow of the opposite 

 side forming a row of mid-ventral tubercles, bearing two setae each ; 

 tubercles xii and xiv are fused into a single small tubercle, which bears 

 two setae. 



Abdominal segment 8: the arrangement of the tubercles is the 

 same except that the fused tubercles i are smaller, and that the ii's and 

 iv's of both sides are fused into a single large tubercle bearing four 

 setae, so that the relative size of the two mid-dorsal tubercles is just 

 opposite that of the other abdominal segments. 



Abdominal segment o is modified dorsally into a strongly chitinized 

 anal shield, which doubtless represents a fusion of tubercles i-viii, with 

 probably the setae of tubercles ii, iv, v, vi and viii persisting; ventrally 

 it bears a large median tubercle, bearing four setae, which probably 

 represents tubercles xiii and xiv of each side all fused together. 



Abdominal segment 10 is very small; it has no setae nor tubercles, 

 but bears ventrally the creamy white anal proleg (which doubtless rep- 

 resents a pair of prolegs fused together) ; the anal opening, shaped like 

 an inverted Y, lies in the middle of the proleg. 



Metathorax : tubercles i and ii are not fused across the middle line, 

 leaving a thin place where the cuticula can yield to the strain and split 

 at the time of molting ; tubercle iii is present but non-setif erous ; tuber- 

 cles iv and vi are fused together into a single tubercle bearing two setae ; 

 tubercles v, vii, and viii are fused into a single large tubercle, bearing 

 three setae ; tubercles ix and x are separate, bearing one seta each ; 

 tubercles xi and xii are associated with the base of the coxa, the former 

 strongly chitinized and non-setif erous, the latter bearing one seta ; tuber- 

 cle xiii on each side is fused with its fellow forming a mid-ventral 

 tubercle, bearing two setae ; tubercle xiv bears one seta. 



Mesothorax: exactly similar to the metathorax except that a spiracle 

 is present above the seta on tubercle ix. 



Prothorax: dorsally modified into a strongly chitinized cephalic 

 shield, formed by the fusion of tubercles i-viii ; tubercle ix wanting ; 

 tubercle x bearing a single seta; tubercles xi and xii lie at the base of 

 the coxa, both bearing a single seta ; tubercles xiii and xiv on both sides 

 have fused together, forming a large bell-shaped non-setiferous mid- 

 ventral tubercle. 



Spiracles. There are nine pairs of spiracles, eight abdominal and 

 one thoracic ; the abdominal spiracles are borne on un-numbered non- 

 setiferous tubercles just above the lateral tubercles (fused vii and viii) 

 of the first eight abdominal segments ; the thoracic spiracle is borne on 

 tubercle ix of the mesothorax ; an homologous tubercle present on the 

 metathorax shows no trace of a spiracular opening. 



Legs. The legs are composed of five segments ; the proximal seg- 

 ment is incompletely chitinized ectad and not at all entad ; it fits closely 

 into a socket formed by the infolded body wall, with which it is con- 



