THE EMBRYOLOGY OF THE HONEY BEE 25 



in their figures the lack of protoplasm within the line of cleav- 

 age cells, without specifically mentioning it in the text. 



Omitting an extended review of the results of other investi- 

 gators who have dealt with this stage of insect development 6 it 

 may be said that speaking broadly, the cleavage process in the 

 bee is fairly typical for the higher insects, and offers but few 

 peculiarities worthy of extended comment. Such differences as 

 exist relate principally to details. Taking up some of these, it 

 may be mentioned first, that while the formation by the cleavage 

 cells of a hollow one-layered figure is common to most of the 

 higher insects, yet this figure in most cases conforms more closely 

 to the outline of the egg than in the case of the bee. This is 

 illustrated by the Coleoptera {Hydrophilus, Clytra), Diptera 

 (Musca), Lepidoptera (Zygaena) and some Hymenoptera 

 (Lasius, Polistes). Second, that part on the egg's surface first 

 reached by the cleavage cells may be located near the middle of 

 the egg, or near one of the two poles. A table compiled by 

 Marshall and Dernhehl (1906) 7 showing the location of this 

 place in twenty-six insects belonging to seven different orders, 

 also shows that different insects within the same order may 

 differ widely in this respect. The Hymenoptera illustrate this 

 point quite well, since, in Formica (Ganin 1869), Lasius (Henk- 

 ing 1892), and Rhodites (Weismann 1882), the cleavage cells 

 first reach the periphery of the egg near the posterior end, in 

 Platygaster (Kulagin 1897), near the equator, in Chalicodoma 

 (Carriere and Burger, 1897), and Polistes (Marshall and Dern- 

 hehl, 1906), near the anterior end, on the ventral side, as in 

 Apis. It is therefore evident that this feature possesses but little 

 significance. 



In the ant Camponotus, according to Tanquary (1913) the 

 conditions obtaining during cleavage are quite different from 

 that of the majority of other non-parasitic Hymenoptera, and 

 decidedly remarkable, recalling the conditions found by Weis- 

 mann (1882) in Rhodites and Biorhiza. According to Tan- 

 quary's rather imperfect observations, a large nucleus, presum- 



8 For a complete review of this phase of insect embryology see Lecaillon 

 1897a, Henneguy 1904 and Marshall and Dernhehl 1906. The last named 

 is particularly complete on the historical side. 



7 L. c. p. 140. 



