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SELECTED NOTES FROM 



nate aclion within certain limits, to each of the spiculse, which that 

 I have referred to of course would not effect. 



Westwood thinks that the eggs pass through the sting in the 

 act of oviposition, and I think that the groove in this organ is 

 continuous with the vagina; but I am unable at the present 

 moment to ascertain this fact satisfactorily. Into this cavity also 

 the duct of the poison-bag appears to open. I think this organ is 

 the homologue of similar ones found in other insects, though here 

 modified for this special purpose. It is of considerable size, and 

 furnished with four longitudinal bands of muscles arranged in 



Fig. 9. 



alternate diagonal directions, as in Fig. 9. 



The homologues of the external sexual or- 

 gans of insects present some very difficult pro- 

 blems, and would need a much greater general 

 acquaintance with the subject than I can lay 

 claim to, to render an opinion worth much. 

 Still, if such guesses at the truth as I have to 

 offer, should be the means of eliciting the 

 opinions of others more qualified to judge, I shall perhaps justify 

 their advancement. I will commence by quoting a note from 

 Mr. B. T. Lowne's Anatomy of the Blow Fly (p. 3) : — " Each 

 segment in the lowest Articiilata is normally furnished with two 

 pairs of lateral appendages or rudimentary limbs, one pair placed 

 above the other, the superior being dorsal and the inferior ventral. 

 At least, such is their arrangement in the Annelida. Both pairs 

 are much modified in the higher forms, and are often entirely 

 suppressed. The segments themselves may be said to consist 

 typically of four plates ; a ventral, a dorsal, and a lateral plate on 

 each side ; the superior appendages being placed between the 

 lateral and dorsal, and the inferior between the lateral and the 

 ventral plates." 



Assuming that there are nine segments in the abdomen of the 

 Wasp, which is the number usually assigned to this portion of the 

 body of insects, (in a species of Stratiomys, I think I have clearly 

 made out ten,) six of which are apparent externally, there remain 

 three which must enter into the composition of the sexual organs. 

 These are enclosed within the last visible ones, as may be seen by the 

 annexed figure (Fig. 10), where a repre- 

 sents the opening of the sexual cavity 

 from which the sting protrudes, being 

 covered above by the dorsal and below 

 by the ventral plate of the sixth seg- 

 ment marked 6 and 6' respectively. 

 Now, if we make a section across the 

 body of the insect in the line of junc- 

 tion of the fourth and fifth segments 

 —viz., in the line x x in the above 



Fig. 10. 



