NO. 2 HONEY BEE — SNODGRASS 89 



margin of the spiracular plate of segment VIII (VII IT), and a re- 

 versed lateral lying external to the spiracular plate and attached on 

 the upper angle of the latter (i/p). In the queen there are two 

 internal dorsal muscles of segment VII (E, i^y, iy8) attached on 

 the spiracular plate. The lateral musculature consists of two tergo- 

 sternal muscles on each side (C, 182, 18^), and a very small reversed 

 muscle, not shown in the figures. The sternum of segment VII in 

 the worker (C) has none of the usual ventral muscles, but in the 

 queen a pair of median internal ventrals is present (D, 18^) attached 

 posteriorly on the copulatory pouch. In both the worker and the 

 queen, however, there is a large, intersegmental sternotergal muscle 

 (C, 184) arising anteriorly on sternum VII and attached posteriorly 

 on the lower anterior angle of the spiracular plate (C, E). 



The muscles of segment VIII in the female all take their origins 

 on the spiracular plates, which are lateral remnants of the eighth 

 tergum. On each side two dorsal muscles (fig. 28 C, E, 18/, 188) arise 

 in the upper angle of the spiracular plate and go to the corresponding 

 quadrate plate of the sting, which represents the tergum of segment 

 IX. Each spiracle has the usual occlusor {i8p) and dilator (ipo) 

 muscles, but the dilator arises on the spiracular plate, there being no 

 sternal plate in the eighth segment. From the lower edge of each 

 spiracular plate a long posterior muscle (ip^) goes forward to the 

 triangular plate of the sting (fig. 31 B, D, ip2), and in the queen two 

 slender anterior ventral muscles (fig. 28 E, ip^, ip^) go mesally to 

 the dorsal wall of the vagina (D). 



The muscles of segment IX in the female pertain to the sting, 

 except two small muscles from the quadrate plate to the ventral wall 

 of the proctiger (fig. 31 B, 200, 201). The other muscles will be 

 described in connection with the sting. 



The male genital organ. — The phallic organ of the Apidae diflfers 

 from that of all other Hymenoptera in a reduction of the outer parts 

 and a great development of the endophallic sack. In Apis mellifera 

 the ectophallic parts consist of two pairs of small plates lying behind 

 the last abdominal sternum (fig. 30 A, B, C, D, Ip, pv) , the small outer 

 pair of which {Ip) may be identified with the parameral plates, and 

 the larger inner pair {pv) with the aedeagal plates, or penis valves, 

 of other families (see Snodgrass, 1941). Between the penis valves 

 and thick membranous folds uniting them dorsally and ventrally is 

 a widely distensible opening, the phallotreme (PJitr) , which leads into 

 the cavity of a huge endophallic invagination (F, Enph) that extends 

 forward as far as the segment of the petiole. 



