April, '13] SCIENTIFIC NOTES 285 



moist condition, caused by the steam from locomotives which were stopped under 

 it forty times or more every day. The article then quotes at some length from Doctor 

 Hagen's paper "The Probable Danger of White Ants" which appeared during 1876 

 in the American Naturalist. 



H. B. Weiss. 



Bleeding trees. The exudation of sap and an accompanying discoloration of the 

 bark below, the latter caused in part probably by precipitates, is more or less famiUar 

 to all conversant with trees and is particularly likely to occur on sugar maples and 

 the American elm. The causes of tliis trouble, owing largely to the fact that the 

 flow originates at a somewhat inaccessible point, are not well understood. There 

 may be several factors involved, and observations made by competent parties at 

 different times show that these exudations may be inhabited by Dipterous maggots. 

 Dr. E. B. Southwick mentions this {Insect Life 7: 136) and attributes it to the sap 

 fly, Mycetobia -pallipes, though there is a statement to the effect that Dr. Hopkins 

 then thought it might be due to a species of Sciara. 



Last fall we observed numerous larvaj superficially resembling Sciara, inhabiting a 

 somewhat profuse flow of sap originating from a crevice in the trunk of a sugar maple 

 at Kinderhook, N. Y. The point below the injury was brown, corrugated and seemed 

 to be covered with precipitates from the sap. Examination of the cavity showed 

 the larvse to be present in the deepest portion of the crevice where they apparently 

 kept the tissues in a constant state of irritation. Sap issuing from a similar wound 

 on a horsechestnut trunk was inhabited by probably identical larva?. 



A study of the larva obtained from the above mentioned sugar maple shows that 

 it can not be a species of Sciara and is probably referable to the genus Ceratopogon, 

 particularly as Joseph Mik describes as C. hippocastani, adults reared from very 

 siinilar larvse which he found in sap from a bleeding horsechestnut. A study of the 

 specimens we collected showed the presence of jaws admirably adapted to gnawing 

 or eroding the more tender cortical tissues. In view of the fact that many of these 

 bleeding wounds are known to be inhabited by Dipterous maggots, some of which at 

 least resemble Sciara larvse, it would not be surprising if this Ceratopogon or its 

 allies at least, prevented the normal healing of wounds and, under .certain circum- 

 stances, may be the prime cause of the trouble. The larva is described below in 

 order to faciUtate the recognition of this insect. 



Larva. Length 5.5 mm., diameter .5 mm., a slender, white larva with a brown or 

 dark head and superficially resembling Sciara. The head has a diameter posteriorly 

 equal to that of the body and tapers anteriorly to an irregularly truncate apex bearing 

 the mouth-parts, the length being nearly equal to its greatest diameter. The man- 

 dibles, are decurved, apparently biarticulate, the distal sclerite narrowly triangular 

 and apically with a stout, curved tooth, the ventral margin being variably armed with 

 smaller, stout spines. The basal sclerite is subquadrate, with a length about four 

 times its width and articulates with the exo-skeleton of the head and also with a 

 sub-median, slender internal rod extending to the posterior fourth of the head and 

 there articulated with a similar slender member of a hyoid-like structure extending 

 in turn to the posterior margin of the head. The mouth laterally and ventrally 

 appears to be guarded or assisted in its functions by two pair of rounded lobes, each 

 margined with a thick tuft of rather long, recurved setae. There are other mouth 

 structures which we will not attempt to describe. Antennse biarticulate, the basal 

 segment with a length f its diameter, the apical segment appearing as a very broad, 

 button-like appendage. The exo-skeleton of the head bears a few small setae, there 

 being apparently four such submedian setse, one pair near the anterior third, the 

 other near the posterior fourth. There are twelve body segments, the divisions not 

 being well marked. The anterior spiracles terminate in eight shghtly thickened, 

 radiating, nearly fused processes on the anterior body segment, and the posterior 

 spiracles are submedian, nearly apposed, the distal portion of the tracheae distinctly 

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