Effects of Castration in Insects 395 



"2. In females with male parasites the basal joint of the hind 

 tarsi is narrower, approaching the shape of the corresponding 

 joint of the male tarsi; this joint not noticeably narrowed in female 

 with female parasites. 



"3. Scopa of parasitized female thinner, plumosity shorter, not 

 so silky. 



"4. Out of six males with male parasites two show the second 

 transverse cubital gone in both wings; one has stubs at each end, 

 however, in right wing; one has the transverse cubital slightly 

 interrupted in both wings. Out of about 1 10 nonparasitized males 

 none show any variation. 



"5. Out of 38 females with male parasites one has the left 

 wing with three submarginals, the right wing with two submar- 

 ginals; one has two submarginals in both wings but right wing 

 with a stub of the nervure; one has first transverse cubital of the 

 left wing one-half gone; forty-five nonparasitized females show 

 no variation. 



"None of the other salient alterations found by Perez could 

 be expected in this species because of the close resemblance of the 

 two sexes. Andrena crawfordi is a very generalized bee." 



Pierce also calls attention to a single parasitized specimen of 

 A. advarians in his collection, with a spurious nervure in the third 

 discoidal cell, and believes that parasitism may affect the trachea- 

 tion of the wings, a modification not observed by Perez. 



II GENERAL CONSIDERATIONS. 



By employing the word "castration" m a broad sense to mean 

 any process that interferes with or inhibits the production of 

 ripe ova or ripe spermatozoa in the gonads of an organism, and 

 not merely in the concise original meanmg as the sudden and 

 complete extirpation of the gonads, we are enabled to bring to- 

 gether a number of interesting but hitherto rather scattered facts 

 which have a bearing on the correlation of the primary and 

 secondary sexual characters. An adequate consideration of these 

 facts would go a long way, I believe, towards preparing us for a 

 profitable study of the recondite problem of sex determination. 



