NOTES AND QUERIES. 391 



Notes from Wilsden. — Recently a Cuckoo's egg was found in the 

 nest of a Ring-Ouzel on the moor above Bingley, which is a very 

 rare occurrence here. The only other instance I have known I 

 reported over twenty years ago ; in this case the egg was found by 

 two of my sons in a nest on Harden Moor. Also the egg of the 

 Cuckoo has been found in the nest of a Robin a few miles from this 

 village — another rare occurrence in the North-west Riding of York- 

 shire. A male Pied Flycatcher took up its quarters for a short time 

 in May in a likely nesting part of Bingley Wood, but ultimately left, 

 I presume for a more suitable breeding haunt ; but a more ideal 

 breeding place than one or two places in Bingley Wood, from the 

 human standpoint, it would be difficult to find for this species. It is 

 gratifying to report again the nesting of the Hawfinch. — E. P. 

 Butteefield (Wilsden). 



INSECTA. 



A Little-known Dipterous Parasite. — On coming downstairs on 

 Aug. 16th, I saw a small Dipteron (Simulium ornatum) on the window- 

 pane, and this insect seemed to enjoy its usual activity until a drop 

 of benzine proved fatal. I then mounted it on a slip of cardboard, 

 when what seemed a huge cabbage-green snake-like creature suddenly 

 crept forth from its abdomen. Its dorsal side was incised like that 

 of a Julus, and its head had some resemblance to a finger-nail. I do 

 not recall having seen any notice of this parasite, but someone may 

 have been more fortunate. After much wriggling the parasite 

 attacked the thorax of the dead insect. — A. H. Swinton (Braishfield, 

 Romsey, Hampshire). 



[I procured the Simulium and parasite from Mr. Swinton, and 

 took them to the British Museum, where I sought the advice of a 

 well-known dipterist, Mr. F. W. Edwards, who has kindly contributed 

 the following note. Mr. H. A. Baylis has written on the identity of 

 the parasite. — Ed.] 



"The worm described by Mr. Swinton probably belongs to the 

 Nematode family Mermithidce, the members of which parasitise a 

 great variety of insects both in the larval and imaginal stages. Siebold 

 (Stett. entom. Zeit. 1848, p. 299) and Strickland (Biol. Bull. Woods 

 Hole, Mass., 1911) record species of Mermis occurring in the larvas of 

 Simulium reptans and S. hirtipes respectively, but Strickland (p. 326, 

 op. cit.) states that " the Mermis does not affect the larval develop- 

 ment to any extent, except by slightly increasing its size, but it 

 inhibits the development of the histoblasts to such an extent that 

 pupation becomes impossible." Some species of Mermis, however, 



