404 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 54. 



the development of the cephalic ganglion, and the metamorphosis of 

 the mesoderm. 



Alimentary system. — Smith and Hamm describe the alimentary 

 canal of a female Stylops melittae Kirby in Andrena nlgroaenea as 

 follows : 



There is a minute moutli opening, and an equally minute anus at tlie hind 

 extremity, but tlie lumen of the gut through the body is obliterated. The 

 whole apparatus is obviously functionless. 



This description is supplemented by drawings of longitudinal and 

 cross sections.^ 



Vascular system. — Smith and Hamm state that in Stylops rnelittae 

 the remains of the dorsal blood vessel or heart can be recognized 

 dorsally to the gut.- 



The aorta is shown very indistinctly by Nassonow in Stylops 

 melittae Nassonow (not Kirby ).^ 



Nervous system. — To the rather limited knowledge of the nervous 

 system in this order Smith and Hamm have added a brief descrip- 

 tion and a drawing of a section of the nervous system of Stylops 

 melittae Kirby. They found only the normal three ganglionic 

 masses, the brain, the thoracic and ventral ganglia.* 



Tracheal system. — Although Smith and Hamm refer to Nassonow's 

 valuable works on the anatomy of the Strepsiptera they do not seem 

 to have used them in their own work on anatomy of Stylops melittae. 

 Consequently, in their description of the tracheal system, they over- 

 look the existence of dorsal and ventral tracheae in the abdomen as 

 described by Nassonow both for Stylops and Xenos. They describe 

 only a single main branch which to judge from their figure is prob- 

 ably the dorsal branch.^ 



Considerable mention is made in the present article of the spiracles 

 in the discussion of the comparative morphology of the male and in 

 the descriptions of species. 



Reproductive system. — Smith and Hamm working on Stylops 

 melittae have studied the brood canal and its trumpetlike invagina- 

 tions and presented a number of illustrations. These illustrations 

 are of value in that they fully corroborate Nassonow's splendid 

 work. The writers suggest that the spiny processes of the epithe- 

 lium of the brood canal are so modified as to assist the triungulinids 

 in reachinor the exterior.*' 



1 Smith and Hamm, 1914, p. 39, pi. 32, figs. 3 and 4, g. 



"- Idem, p. 439, pi. 32, figs. 3 and 4. 



s Nassonow, 1893, a, pi. 2, fig. 1, n. 



* Smith and Hamm, 1914, p. 439, pi. 32, fig. 3. 



8 Idem, p. 439, pi. 32, fig. 4. 



8 Idem, pp. 437, 438, pi. 32, figs. 3, 4 ; pi. 33, figs. 6. 7. 



