240 F. W. EDWARDS. 



Many of the streamlets in whicli S. latipes abounds are completely dry for tlie 

 greater part of tlie summer, and though they may fill up during the autumn rains, 

 I have not yet detected the presence of young larvae before about Christmas. It 

 will be of considerable interest to discover exactly what happens to the insect 

 during the dry season. I consider it most probable that it exists in the egg- stage, 

 and that the egg-burster is a modification similar to that found in mosquitos of the 

 Aedes group, which are capable of sustaining prolonged desiccation in the egg stage. 



Material collected. — ^Larvae and pupae occurred in abundance in most of the 

 streamlets round Harrow, Pinner, Northwood, Ruislip and Stanmore, Middlesex, 

 in the spring of 1915 and 1916. The earhest pupae were found about the end of 

 March. Hatch End, Middlesex, 7.viii.l5, larvae and pupae in stream which had 

 been dry from middle of May to beginning of July ; larvae not nearly so common 

 as in the spring. Streamlets in and near Kneb worth Wood, Herts., haK-grown 

 larvae 4.iii.l7, larvae and pupae on stones and grass, ll.iv.17, numerous under 

 stones, 10.V.20. Norton Common, Letchworth, Herts., small larvae xii. 1916, 

 somewhat larger ii. 1917, pupae and some larvae 17.iv.l7, a few larvae left 7.vi.l7 ; 

 many small larvae, chiefly second stage, but a few first and third stage, 21. xii. 19 ; 

 the stream was quite dry from June till early November 1919 ; larvae of all stages 

 i-vi, but chiefly v, 29.ii.20. Burnham Beeches, Bucks, iv.l916. River Lea, near 

 Hatfield, Herts., v. 1916, two pupae on Ranunculus in company with numerous 

 S. ornatum and S. equinum ; one of these had the anterior projection of the cocoon 

 forked, perhaps owing to its unusual environment. Streamlets on flanks of Goat 

 Fell, Isle of Arran, v. 1919, up to a height of 1,000 ft. Inverleithen, near Peebles, 

 7.viii.l910, larvae of various sizes on grass [Dr. J. Rettie, per Dr. J. H. Ashworth). 

 New Forest, Hants., 1. v. 1920, larvae, mostly full-grown, and pupae, on grass and 

 Ranunculus in small streams running into BeauHeu River, also in the Beaulieu 

 River itself about a mile above Beaulieu. River Test, Hants. {M. E. Mosely). In 

 numerous small stony streamlets in the valleys of the Dart and Teign, S. Devon ; 

 also a few in the River Teign below Fingle Bridge, vi.l920. 



Variation. — There seems to be but little variation in the adult or pupa, except to 

 a slight extent in size and in the length of the stalks of the pairs of pupal filaments 

 and the length of the anterior projection of the cocoon. The larvae also are fairly 

 constant in any one locality, though the head markings vary in intensity, and the 

 young larvae have usually darker heads than the larger ones, with less defined 

 markings. The New Forest larvae had rather distinct reddish-brown bands on the 

 abdomen, much as in S. aureum ; these markings are usually hardly perceptible in 

 Hertfordshire specimens. 



Blood- sucking. — ^For a long time I considered that this species was not a blood- 

 sucker, and in fact it was long before I captured a female on the wing, in spite of 

 searching for them near the places where the larvae were abundant. Swarms of 

 males were found hovering in the shelter of hedges, but at first no females were seen. 

 However in the Isle of Arran, at the end of May 1919, females were very numerous in 

 Sannox Wood and by some of the wooded burns, flying round us in swarms, and so 

 far as could be ascertained all the bites received were inflicted by this species ; it 

 could easily be recognised b}^ the naked eye on account of the pink abdomen. 



