164 



THE BRITISH NATURALIST. [August 



Eupithecia Pumilata. — Swarms on the moors. 



Eupithecia Rectangulata.— Mr. Tait has a specimen in his 

 collection, which he captured near Inverurie. 



Eupithecia Debiliata. -Exceedingly local, I have found the 

 larvae among Vncciniimi myrtilhts on Ben-na-chie (Benachie). 



Lobophora Hexapterata. — Once at Fyvie (" Lep. of Dee."). 



Lobophora Lobulata. — Scare, Braemar (Dr. White), Inverurie 

 (Mr. Tait), Pitcaple (Mr. Reid). 



Thera Juniperata. — Locally common, among juniper. 



Thera S^mulata. — Common at Braemar, and Mr. Tait has taken 

 it at Inverurie. 



(To be continued.) 



Vertebrata. 



"WHAT IS A BIRD ? " 



BY L I N N ^ U S GREENING. 



( Continued from page 126.) 



Returning again to the consideration of the embyology of the 

 Sauropsidans, w^e find that it strongly supports the assertion that all 

 birds and all reptiles are but modifications of one remote ancestor ; 

 and in tracing the life of a chick in the egg we shall see some of the 

 evidence in support of this, and shall perhaps be prepared to accept, 

 with the majority of modern naturalists, the doctrine that the life history 

 of the individual is an epitome of the history of the species. All 

 birds are strictly oviparous, and all birds eggs normally possess a hard 

 shelly covering, though if the birds cannot get enough lime they will 

 deposit their eggs with a soft covering, as do most reptiles. In all 

 Sauropsidans the fertilization of the egg is effected before it leaves the 

 body of the mother. After fertilization, segmentation of the germinal 

 disc begins ; and, in birds, the fertilized egg, in passing down the 

 oviduct, becomes surrounded with the white, the shell membrane, and 

 the shell, all of which are secreted by appropriate glands, so that 

 normally, when a birds egg leaves the body of the mother the embryo 

 is surrounded by several protective coverings. The development of 

 the embryo may be. arrested if a sufficiently high temperature is not 



