NO. 8 



INSECT ABDOMEN SNODGRASS 



133 



second valvula. A representative of this muscle has not been found 

 in other orders of insects. 



The muscles of the furcula are usually regarded as the protractors 

 (Vorstossmuskeln) of the sting. It was correctly observed by Kraepe- 

 lin ( 1873), however, that they can act only in the capacity of deflecting 

 the distal end of the shaft since they pull upward on the base of the 

 bulb. 



20 Frc 19 r2vl rivl 



^aVlf 



Fig. 45. — Musculature of the hymenopterous ovipositor or sting. 



A, sting of Apis mellifica, worker, with venter of ninth segment and proctiger, 

 dorsal view, showing muscles of the stinging apparatus. 



B, second valvifers and base of shaft of ovipositor of Atanycolus rugosiventris, 

 with muscles inserted on the latter, dorsal view. 



C, anterior end of right second valvifer, mesal view, with right ramus and 

 base of shaft of ovipositor of Mcgarhyssa atrata, showing anterior muscles (77) 

 of valvifer, and muscles of the shaft {19, 20). 



20. Ramus muscle of the second valvula. — A rather small muscle 

 in the worker bee attached dorsally on upper part of ramus of second 

 valvula (figs. 42 B, 45 A), and ventrally on lateral process (y) of 

 base of bulb (fig. 42 B), In Atanycolus (fig. 45 B) and in Mcgarhyssa 

 (C) this muscle is relatively larger and stretches like a bowstring 

 between the two extremities of the strongly arched ramus. The 

 ramus muscle appears to have no homologue in insects other than 

 Hymenoptera. 



21, 22. Muscles of the proctiger. — Two slender muscles arising 

 from posterior dorsal angle of quadrate plate (fig. 45 A) ; extending 



