Insects 181 



exceptions, it occurs practically all over the United States. A 

 practical result of this condition is that persons from the tropics 

 or other malarious regions may come here to recuperate, and if 

 they carry germs of malaria in their bodies, they will not be a 

 menace to the rest of the population, as they would be in the 

 presence of Anopheles. Indeed, strange as the idea may at first 

 appear, Colorado would be a very good place for the location of 

 a School of Tropical Medicine, where medical men from the tropics 

 might come and work up their materials while at the same time 

 improving their health. 



A list of the mosquitoes of Colorado was given by the writer 

 in Journal of Economic Entomology, 1918. More recently 

 (Insecutor Inscitiae Menstruus, 1924) Dr. H. G. Dyar has pub- 

 lished a new list, with a number of additions. Dr. Dyar made 

 collections at Grand Lake in the early spring of 1923, and says, 

 " I was fortunate enough to arrive before the Public Health 

 Service had completed its extermination work. These mountain 

 mosquitoes are so easy to destroy that it seems almost like taking 

 an undue advantage of nature. Certainly the able and sharp- 

 eyed man who had been employed to spread oil on the pools left 

 little enough for a late collector". The combined lists give about 

 20 species of Aedes (which are the common mosquitoes), four of 

 Theobaldia, one of Culex, and one of Anopheles. The high moun- 

 tain species represent what Dyar calls the Canadian fauna, ex- 

 tending north through Wyoming and Montana to Canada. 



Cecidomyiidae or Gall-gnats 



These minute and delicate flies, with many-jointed antennae, 

 are of importance because many of the species have larvae which 

 live in the tissues of plants, producing galls. These larvae are 

 usually of an orange color, and may be found on breaking open 

 a gall. Some of the principal Cecidomyiid galls of Colorado are 

 the following: 



(1) Bud galls on Pinus scopulorum, due to Contarinia colo- 

 radensis Felt. 



(2) Kidney shaped enlargements at base of needles of Pinus 

 edulis, due to Thecodiplosis cockerelli Felt. 



(3) Reddish conical gall on Juniperus utahensis at McCoy. 

 Oligotrophus betheli Felt. 



