RELATIONS OF OVA AND GEMM2E. 197 



produce females are so fertilized, and that those going to 

 form males (drones) are expelled without contact with the 

 spermatic fluid its access being cut oif by a contraction of 

 the sphincter of the spermatheca, which is induced in the 

 reflex way, by a peculiar impression made on the abdomen, 

 when inserted into such a cell as is prepared for the nurture 

 of a drone larva.* The impregnated ova again all give origin 

 to female larvae, which, according to their diet and general 

 treatment, become either fertile queen bees, or sterile workers. 

 The evidence on which Siebold founds his conclusion as 

 to the non-impregnation of drone-ova is principally the 

 following : 



1. Workers, whose organs do not admit of copulation, 

 though generally sterile, do occasionally produce ova, but 

 these always develope drone-larvae. In some species fertile 

 workers form a large proportion of the whole. ( 



2. It may be regarded as an ascertained fact that bees 

 copulate in the air, and never in the hive ; and, in connec- 

 tion with this, it has been observed that the ova produced 

 by queens, which, from imperfect development of their 

 wings, are incapacitated for the marriage flight and conco- 

 mitant impregnation, are also always drone. 



3. The ova produced at the close of the season, even by 

 a fully impregnated queen, are drone, the contents of the 

 spermatheca being by this time exhausted. 



4. They are found to be drone also when the spermatheca 

 is destroyed by any injury to the abdomen. 



* Kiichenmeister, observing that it is only when the abdomen is com- 

 pressed that fluid escapes from the spermatheca, suggests that the 

 fecundation of the eggs which yield the larvse of queens and workers 

 may be due to the mechanical pressure of the edge of the cell on the queen's 

 body : such pressure would not occur when the abdomen is inserted into 

 the more roomy cells provided for the larvse of the drones. Annals of 

 Nat. Hist., 3d Ser., II., 490 



f Leuckart, quoted in Quart. Journal of Microscop. Science, Jan., 

 1859, p. 104. 



