80 MEMOIBS OF THE NATIONAL ACADEMY OF SCIENCES. 



Anophthalmias tenuis. — A.mong eighteen specimens from Bradford Cave the largest measured 

 .20 inch, the smallest .16 inch. There are greater differences among the specimens of this spe- 

 cies than in A. tellkampfii from Mammoth and other caves, nearly a third out of eighteen specimens 

 being smaller than the rest, where in A. tellkampfii only one or two out of that number are 

 dwarfed. 



From the foregoing remarks it will be seen that there is a very slight amount of variation in 

 the species of Anophthalmus either in color or proportions ; that the species inhabiting Bradford 

 Cave, which is small and shallow, varies far more than those inhabiting the genuine and larger 

 limestone caverns; moreover, the differences in size are probably due to variations in the supply 

 of food, scattering individuals being somewhat dwarfed, probably from the scarcity of food during 

 the larva state, the other physical surroundings of light, temperature, and soil being unvarying. It 

 should be, however, noticed that, whereas we did not perceive any difference in proportion of parts, 

 the more practiced eye of Dr. Le Conte detected in A. menetriesii such differences as to lead him to 

 remark of this species that " a large series of specimens is seen to vary slightly in for m." So much 

 alike are all the species of Anophthalmus, that it is not impossible that all of them had a common 

 ancestor. 



Adelops hirtus. — Those found in the Labyrinth, in Mammoth Cave, varied in length; the largest 

 of twenty-two specimeus being .12 inch and the smallest .09 inch. Two-thirds of the number were 

 males. This beetle varies more in proportion of parts than the species of Anophthalmus. 



A few other unidentified Staphylinid beetles and Coleopterous larvae are figured on Plate XX. 

 (See explanation of PI. XX.) 



DlPTEKA* 



1. Wyandotte, New Cave. Sciara. Borborus. 



2. Fifty feet frotn mouth of Wyandotte. Phora. 



3. Labyrinth, Mammoth Cave. Pupa of Sciara. 



4. Wyandotte Cave. Chironomus (different from No. 8 ; larger). 



5. Labyrinth, Mammoth Cave. Sciara, 2, in copula. 



6. 6 bis. End of Dixon's Cave. Mammoth Cave. Borborus. 



7. Diamond Cave. Sciara. 



8. Dead Sea, Mammoth Cave, April 25. Chironomus, small species. 



8. bis. Dead Sea, Mammoth Cave, A. S. Packard. Chironomus, small species. 



9. Diamond Cave, May 2, half mile in (F. G-. Sanborn). Small Dolichopodid ; female. 



10. Cave next to Ice Cave, 60 feet deep, 3 miles from Mammoth Cave. Rhypholophus (Eriopterina), allied 



to E. nubilus O. S. Blepharoptera. 



11. Fountain Cave. Mycetophila. Blepharoptera. Anthomyia. 



12. Carter Cave, front of hotel. Phora. Blepharoptera. 



13. Bat Cave. Phora. Blepharoptera. 



14. Old mouth, Cave of Fountains, partial daylight. Blepharoptera. 



15. Bradford Cave, Indiana. Mycetophila. Blepharoptera. A pupa ? . 



OBSERVATIONS. 



Borborus (No. 1, 6) usually occurs on dung, excrements, etc. ; some on decaying fungi. 



Sciara (3, 5, 7) ; their larvae live in decaying vegetable matter, fungi, etc. The SciaraB are usually black ; that 

 taken in copula is remarkable for its very pale coloring. 



Mycetophila (No. 11 and 15) larvae in fungi. 



Blepharoptera (family Helomyzidse) ; larvae in fungi. The same species occurred in all the bottles, 11 to 15. It 

 seems to be n. sp., and is the only species in the lot which is perhaps worth describing. 



Blepharoptera defessa n. sp.,t male and female. — A sparse pubescence on the under side of the pleurae, a single 

 vibrissa on each side of the epistoma, a single strong bristle above the middle tibiae ; costa beset with moderately 

 long bristles ; length, 5 to 6 mm . 



Antennae red, third joint brownish-red ; arista rather long ; front yellowish-red ; frontal orbits grayish ; a paler 

 triangle on the vertex, bearing the brownish ocellar tubercle ; anterior frontal bristle short, the one behind not quite 

 twice as long. Thoracic dorsum yellowish-gray ; the eight large dorsal bristles are inserted on brown spots, which 



* These identifications and remarks were prepared several years ago by Baron Osten Sacken, and are based on 

 the material collected in 1874. 



t Afterwards the following description was published in Hayden's Bulletin U. S. Geol. Surv. Terr., iii, 168, 1877. 

 It occurred in a cave at Manitou, Colorado. 



