Life-history of Dasyheha ohscura, Winnei'fz. 577 



pal apes, Meig., (3) Systenus adpropinquans, Loew., (4) S. 

 scholtzii, Loew., (5) Aulacogaster rujitarsis, Meig., (6) P/iaonia 

 cincta^ Zett., and (7) an undetermined Sjrphid larvse closely 

 allied to the genus Ceria. This wound was also visited by 

 the predaceous larvae of two Staphyluiid<e ^ — one belonging 

 probably to the genus Quedius sp. (subfamily Staphylininje), 

 the other being possibly a Thamiarcea sp. (subfamily Aleo- 

 charinfe). 



Finally, the whole surface of the decomposed sap of this 

 wound, and especially its solidified portions, was covered by 

 myriads of a mite, Hericia hericla, Kramer (Tyroglyphidaj), 

 in all the stages of its developmeut. 



The larvpe of Dasijhelea were also common in a simdar 

 wound of a horse-chestnut tree standing on the ground 

 between tlie School of Agriculture and the Downing College 

 grounds, and Mr. W. F. Edwards has kindly communicated 

 to me the following unpublished records concerning the 

 various breeding-places of this midge : — 



(1) J. E. Collin bred it with Culicoides varius, Winnertz, 

 and Culicoides fascipennis from debris of a chestnut tree 

 (Snail well, Cambs). 



(2) F. Jenkinsou reared them from elm sap (Logic, Elgin 

 and Cambridge). 



(3) F. W. Edwards himself obtained Z). o^scwra : (a) with 

 Rhyphus fenestralis from the decaying roots of Angelica 

 (Knebworth, Herts), (b) from running sap of an oak, (c) with 

 Mycetobia pallipes, Systenus sp., and an undetermined Syrphid 

 from running sap of hornbeam, and, finally, {d) with Rhy- 

 phus fenestralis and Mycetobia from stagnant water in a hole 

 in an oak tree (Epping Forest) . 



To find the early stages of Dasyhelea obscura it is sufficient 

 to collect a small quantity of semifluid axudate filling tlie 

 wound of au elm tree, to stir it in a petrie-dish with a little 

 tap water, and leave it for au hour or more to settle. 

 Examined under the binocular microscope, the eggs, larvjc, 

 and pup?e of Dasyhelea are very easily detected on the 

 bottom of the dish. 



II. Eggs AND OviPosiTioN. (PI. XIX. fig. 4, and text-fig. 1.) 



The female seems to oviposit only once in her life, and 

 the eggs, about 120 in number, are laid simultaneously 

 upon the solid particles sticking out from the exudate or 

 upon the moistened edges of the wound. 



* The identification of these larvte I owe to tlie kindness of 

 Ml". K. G. Blair of the British Museum. 



Anil, cd- M(Hj. iV. IJist. Ser. 9. Vol. viii. 37 



