35 
Hydroponis decoratus, Gyll. —This scarce and charming 
insect is abundant in many Askham Bog Ponds throughout 
spring and autumn. In April it is in profusion. 
Ilydroporiis riififrons, Du ft.—A. rarity not seldom afforded 
by Askham Bog in the greatest abundance. It affects shallow 
floodings, where it appears with incredible rapidity, and some¬ 
times in vast numbers. I have seen it most abundant in 
the end of Summer and the beginning of Spring. 
Hydroporus neglect us, occasionally turns up at Askham 
Bog, but has been found much more abundantly near Strensall 
Common. 
Colymbetes Grapii, Gyll, inhabits a mossy swamp at Askham, 
and is a Spring insect. 
Colymbetes bistriatus, Berg., occurred in a Strensall pond, now 
drained. 
Agabus abbreviatus, Steph. This pretty insect is well distributed 
in Askham Bog, and has found its way into the Hobmoor 
brick ponds, so that its extinction need not be much feared. 
Agabus unguicularis ,— Th. Is still mere abundant at Askham. 
Agabus uUginosus, —Is the companion of H. rufifrons in 
floodings. The dull form of the female is particularly abundant. 
Agabus femoralis, Pk, inhabited ponds on Strensall Common, 
now drained—one of the many sins the War Office will have 
to answer for. 
Agabus agilis, F. abounds at Askham Bog. 
Dytiscus circumcinctus, Ahr. —A single specimen was taken 
about flfteen years ago in very deep water in Askham Bog. 
Dytiscus dimidiatus, Berg, has also been taken, once or twice, 
in the large ponds at Askham. 
Hydaticus transversalis, Berg. —Still lingers at Askham Bog. 
Last year I took a pair—the only ones I have seen for three 
years. 
The other Hydradephaga worth enumerating which occur 
near York are Faliplus Julvus, flavicollis, cinereus. Hydroporus 
reticulatus, incecqualis, picipes, pictus, granularis, depressus, 
assimilis, dorsalis, Gylenhalli, tristis, umbrosus, obscurus, vittula, 
memnonius, Ilybius ater, obscurus, and guttiger. 
W. C. HEY. 
