FAUNA OF PENIKESE ISLAND. 



27 



MOLLUSCS. 



(Gastropod from pond not identified.) 



ARTHROPODS. 



Crustacea. 



(Identification by U. S. National Museum.) 

 Oniscus asellus Linnaeus. 



Porcellio rathkei Brandt. Abundant under boards and logs and 

 in stone fences. 



Myriapods. 



(Identification by R. V. Chamberlain, Museum of Comparative 

 Zoology, Cambridge, Mass., through U. S. 

 National Museum.) 

 Lithohius forficatus Linnaeus. 



Anax Junius (Drury). Pond i-B; three nymphs. 



Pond 2-B ; four nymphs. 

 Pond i~D; seven nymphs. 



Celithemis eponina (Drury) ; seen flying about in two places. 

 Ischnura verticalis (Say) ; Pond 2 ; two adults. 



Pond 2 ; four adults. 



Gryllidae. 



Gryllus assimilis. 

 Nemohius vittatus Harr. 



1 In reports on aquatic insects (Odonata, Hemiptera, Coleoptera) the several 

 small ponds are distinguished by letters and numbers, as follows: The two small 

 water-holes near the northwest corner of the island are designated i-B and 2-B, 

 I being southwestward of 2; i-C (Cattail Pond) is on the eastward side of the 

 island near the keeper's house; near the southerly tip of the eastward extension 

 of the island (Tub Point) are two small ponds, i-D and 2-D, i being northeastward 

 of 2. The largest pond, that near the southerly point of the main island, known 

 to the collectors as South Pond (A) was decidedly brackish and yielded only one 

 aquatic insect. The specific gravities (uncorrected for temperature) and the tem- 

 peratures of the waters of these ponds were as follows: South Pond, 1,015 (20° 

 C); i-B and 2-B, 0.99 (21° C); i-C, 0.99 (20° C); i-D, 1.0018 (23° C); 2-D, 

 1.005 (22° C). — Editor. 



Insects. 



Odonata.^ 



(Identification by C. B. and J. E. Wilson.) 



Orthoptera. 

 (Identification by C. E. McClung.) 



