THE AQUATIC ADAPTATIONS OF PYRAUSTA PENITALIS GRT. 



(LEPIDOPTERA.) 



PAUL S. WELCH. ; 



(Abstract.) 



Aquatic Lepifloptera have developed ingenious method.?, both morpho- 

 logical and physiological, of solving their problems of maintenance. Pyrausta 

 PcnitaUs Grt. is successfully adapted to aquatic surroundings although devoid 

 of special structural features peculiar to such an adjustment. It likewise 

 retains the ability to exist luider terrestrial conditions, at least to a limited 

 extent. The major adaptations appear in connection with food getting, 

 locomotion, and respiration. Feeding on the exposed surfaces of Nelumho 

 leaves it is safeguarded from wave-action by the construction of silk surface 

 webs ; of marginal, rolled-up tunnels ; and of short, vertical, petiole burrows. 

 An efficient form of surface swimming constitutes the principal method of 

 locomotion. Direct access to the atmosphere, demanded by the method of 

 respiration, is insured by feeding on a watei-proof leaf-surface, and by tunnel 

 construction in the slightly elevated petiole junction. Pupation in petiole 

 burrows is accompanied by cocoon formation and the construction of a 

 special closing device at the top of the tunnel. This closing device is not 

 developed when pupation occurs either in the peripheral tunnels or in ter- 

 restrial plants. 



THE OCCURRENCE OF A SPECIES OF ECHINOSTOMIDAE IN 



LARUS ARGENTATUS. 



WM. KORDES BOWEN. 



(Abstract.) 



Certain Echinostomidae were collected by Dr. G. R. La Rue from the 

 intestine of young herring gulls (Larus argentatus). The gulls were obtained 

 from Goose Island, near Douglas Lake, Michigan, during the summer of 1917. 

 They were three or four weeks old, and were fed for some time on a diet 

 consisting chiefly of raw fi.sh. 



It has as yet not been possible definitely to place the parasite under 

 consideration in any present genus. According to the classification proposed 

 by Dietz, and adopted by Luehe in his manual on Treraatodes, which is the 

 seventeenth volume of the "Suesswasserfauna Deutschlands," the trematode 

 in question appears to be very closely related to the genera Mesorchis and 

 Monilifer, but does not fit \\ith certainty into either. 



Dept. of ?iOol., University of Michigan. 



