Pomona Colleoe Journal op Entomoloov 680 



known. It is <|iiitr proh.ildi-, lidwrvcr, tli.'il canful M-.ircli will rcvi-nl tlii-ni in 

 many otlicr localities. 



As mentioned in the resume of Dr. Howard'.s article, the H_v, I'lilopa 

 pelrolei C"o(|., belongs to the family Kphi/driiliie (Diptera). nil the members of 

 which are more or less suba(|uatic in the larval stage and live in all .sorts of 

 peculiar and uncx])ected places, such as brackish wati-r of all kinds, slime and 

 00/.I-, human urine and excrement, etc. 



The method of oviposition is as yet unknown, but in all (jrobabilitv the egj; 

 are de))osited on the soil or sticks or leaves close to the petroleum pools, and Ihi- 

 larviv on hatching innncdiately find their way into the oil. It scarcely seems pos- 

 sible that oviposition is on or in the oil itself. However that may be, I havi- 

 found exceedingly minute larvae, scarcely more than one or two millimeters in 

 length, swinnning about in the petroleum. 



The swimming, if it may be called such, is very slow and risemliles doselv 

 the movements of any maggots in lifjuitied carrion or decaying fruit. The larv.a 

 usually remains and moves about ne.ar or on the surface of the oil, although fr«- 

 (piently it goes entirely under the surface for a considerable length of time. In 

 fact the specimens which were sent to me by Professor Ksterley came in n small 

 bottle half full of petroleum and were more than twenty-four hours in transit 

 before they were opened in the laboratory here. .Many of them were at the 

 bottom of the bottle and still alive and active when transferred to a shallow dish 

 of |)etroleum. The explanation of the possibility of this will appear soon. 



In watching the habits of the larva it was noted that when one, in swim- 

 ming about in the dish, came to the edge of tlu' oil it immediately turned back 

 towards the center of the dish. Some were found, however, to leave the oil 

 and crawl oflF across the table. These soon became clean, without oil clinging to 

 them, and n little later seemed to be drying up. A few hours after their emer- 

 gence from the oil they became almost motionless, apparently very weak, and 

 more or less shrivelled and dried. Death followed in twelve to eighteen hours. 

 Till' eaus<> of death is probably two-fold; no opportunity of getting food when 

 removed from the oil. ami the drying of the body tissue when not protect<'d by 

 the |)etroleum. 



I do not know how many days or weeks the larva lives, but when it attains 

 the length of seven to ten millimeters, it crawls out of the oil to pupate. Tin- 

 pupating habits in its native haunts have not been determined yet, but in tli<' 

 labor.'itory it pupates in various places outside of the oil, such as on the cover of 

 the cagi- as noted by Dr. Howard, or on the table surface within the confining 

 bell-jar as I fouiul. In one dish I ))laced a little soil which soon became .sat- 

 urated; also n small cork an inch long was ))laced in it. No ])U))ip were found 

 outside the dish, so it would seem that ])U|>ation took place either in or on the 

 soil, though none was found there. Two pupa* wi-re foinid in the sm.all cavities 

 of till- cork, but there were several .adults th.at emerged from this one dish, show- 

 ing that ])upation nnist have occurred somewhere else, also. These facts, how- 

 ever, throw but little light on the natural habits, and these habits must be de- 

 termined by .letu.'il tiild obsi-rvation. Prob.ibly pupation takes place in the oily 



