Mason-Wasps. 



25 



the interior lining. In November following, we hewed away 

 the brick around this nest, and found the whole excavation 

 was rather less than an inch in depth. 



Notwithstanding all the precautions of the careful parent 

 to conceal her nest it was found out by one of the cuckoo 

 flies ( Tachina larvarum f ) probably a common species very 

 similar to the house-fly, but rather larger, which deposited 



Cuckoo-Fly (Tachina larvarum?). - Natural size. 



an egg there ; and the grub hatched from it, after devouring 

 one of the wasp-grubs, formed itself a cocoon (a), as did the 



Mason -Wasp's Nest and Cocoons. About one-third the natural size. 



other undevoured grub of the wasp (6). Both awaited the 

 return of summer to change into winged insects, burst their 

 .cerements, and proceed as their parents did. 



Another mason-wasp (Odynerus murarius, LATE.), differ- 



Mason-Wasp (Odynerus murarius). Natural size. 



ing little in appearance from the former, may often be seen 

 frequenting sandy banks exposed to the sun, and construct- 



