DEPARTMENT OF MARINE BIOLOGY. 



191 



REPORTS OF INVESTIGATORS FOR THE SEASON OF 1913-1914. 

 Insects of the Tortugas, by Stanley C. Ball. 



During the period from June 18 to July 28, 1914, I made an attempt to 

 collect, on Loggerhead Key, Dry Tortugas, as many species of insects as 

 possible. There were two incentives to this work besides that of pleasure. 

 First, I had learned from Dr. Mayer that, to his knowledge, no such attempt 

 had previously been made; for this reason, and the fact that the Tortugas are 

 the most isolated islands on the coast of the United States, it seemed possible 

 that the insect fauna of the island might contain species not yet described. 

 In the second place, the small size of the key and its limited number of plants 

 lent themselves to a fairly easy and thorough examination within the time 

 at my disposal. 



All species of plant except the Cceidea trees set out in the lighthouse 

 grounds were examined both by daylight and, with the aid of a bull's-ej^e 

 lantern, at night. I found "beating" the method most productive of results. 

 For this purpose an umbrella was used wherever convenient; in thick bushes 

 and grass a small net served the purpose. Sheets of "Tanglefoot" sticky 

 fly-paper set out on boards captured many specimens which were later dis- 

 solved off in alcohol. In the evenings, Odonata, Hemiptera, Coleoptera, and 

 Lepidoptera were attracted to lights at the laboratory. 



Three species of plants together yielded perhaps three-quarters of the 

 entire collection. A small pusley-like plant on the beach swarmed with 

 Diptera, Hemiptera, Coleoptera, Lepidoptera, and Hymenoptera. The ex- 

 tensive growth of bay cedar (Surianum) yielded Coleoptera, Orthoptera, 

 Odonata, Neuroptera, and Hemiptera. Frequenting the sea-bean vines I 

 found lesser numbers of Hymenoptera, Diptera, Hemiptera, and Lepidoptera. 

 A small group of Cceidea trees was infested with immense numbers of a 

 black beetle, which to investigators attempting to use a light in the evening 

 proved a great nuisance. The other species were taken from such places as 

 the seaweed along the beach, leaves of exotic plants introduced with the 

 laboratory, and the laboratory buildings themselves. Hordes of ants and 

 cockroaches appeared wherever any dead animal or plant matter was left. 



In the table below I have noted the number of species to each order as 

 nearly as I have been able to work them out. Doubtless in a few cases more 

 than one species is rated as one. I have aimed rather to find the minimum. 

 My determination shows at least 121 species. 



