36 WHEELER— THE PARASITIC ACULEATA. 



and ending with Ancrgatcs atratiiliis, a small, sporadic, and appar- 

 ently evanescent species, without workers and with wingless, 

 nymphoid males, suggests that parasitism among the Aculeates 

 tends to such extreme specialization ("degeneration") as to lead 

 to extinction. If we possessed a knowledge of the whole evolution 

 of the Aculeate group, we should probably find that the total num- 

 ber of parasitic species which it produced during the ages was very 

 great, but that the vast majority of them, after reaching the Ancr- 

 gates or a similarly specialized, or degenerate stage, lingered on 

 precariously for a time and then disappeared. 



LITERATURE. 



1902. Adlerz, G. Ceropales maculata Fab. en Parasitisk Pompilid. Bih. K. 



Svcnsk. Vet. Akad. Hand!., 28, 1902, 20 pp. 

 1904. Adlerz, G. Om cellbyggnad och tjuvl)in hos Trachusa serratuls Panz. 



E>it. Tidskr., 25, 1904, pp. 121-129. 

 1910-12. Adlerz, G. Lefnadsforhallanden och Instinkter inom Familjerna 



Pompilidse och Sphegidae III. and IV. K. Svcnska Vctcnsk. Handl., 



45, No. 12, 1910, pp. 5-75; 47, 1912, No. ID, pp. 5-61. 

 1910. von Alten, H. Zur Phylogenie des Hymenopterengehirns. Jen. Zcit- 



sclir. Naturw., 46, 1910, pp. 511-590, 4 pis., 28 text-figs. 

 1899. Ashmead, W. H. Classification of the Bees, or the Superfamily 



Apoidea. Trans. Amcr. Ent. Soc. 26. 1899, pp. 49-100. 

 1916. Bequaert, J. On the Occurrence of Vcspa austriaca Panzer in the 



Northeastern United States. Bull. Brooklyn Ent. Soc, 11, 1916, pp. 



101-107. 



1902. Brauns, H. Eucondylops n. g. Apidarum. Zcitschr. Hym. Dipt., 6. 



1902, pp. 377-380. 

 1878. Breitenbach, W. Ueber Halictus 4-cinctiis F. und Sphccodcs gibbiis L. 



Stcft. Ent. Zeitg., 1878, pp. 241-243. 

 1912. Brun, R. Weitere Beitrage zur Frage der Koloniegriindung bei den 



Ameisen, mit besonderer Beriicksichtigung der Phylogenese des 



sozialen Parasitismus und der Dulosis bei Formica. Biol. Ccntralbh, 



32, 1912, pp. 154-180, 216-226. 



1903. von Buttel-Reepen, H. Die Stammesgeschichtliche Entstehung des 



Bienenstaates. Leipzig, 1903. 

 1903. Carpenter, G. H., and D. R. Pack-Beresford. The Relationship of Vcspa 



austriaca and Vespa rufa. Ent. Month. Mag.. (2), 14, 1903, pp. 230- 



242, I pi. 

 1902. Cockerel!, T. D. A. Coiitril)utions from the New Mexico Biological 



Station. — XII. On some Genera of Bees. .];;;;. Mag. Xat. Hist., 



(7), 9, 1902, pp. 230-234. 

 1906. Cockerell, T. D. A. The Bees of Florissant. Bull. Amcr. Mus. Nat. 



Hist., 22, 1906, pp. 419-455, 2 figs. 



