lOliO. SYSOrSlii OFXEOTROf'ICALLLMyOIilX.JC—ALEXAXDER. 4S3 



Antochini common, especially RJuimphidia and Teucholabis; Eriop- 

 terini numerous; Limnophilini common {LimnopMla, Polymera, and 

 Epiphragma). Hexatomini very numerous, almost all behip; Eriocerse; 

 tlie Tipulinse are represented by an abundance of Tipuh. Pachyrhina, 

 Brachjpremiui. Tanypremna. and Megistocera. 



GEOGRAPHICAL DISTRIBUTION'. 



Concerning the geographical conditions of the regions where certain 

 of the included material was collected, the following are of interest: 



roo;ruj(oom/in.— Cataracts 0:1 the Potaro River. S miles above the junction with 

 the Essequibo. 



Kakteur (Falls).— Fonned by the fall of the River Potaro, a tributary of the Ease- 

 qiiibo, over an abrupt cliff of 741 feet. The width of the fall at times of high water is 

 370 feet while at low water it decreases to rather less than half that width.' 



The rainy season of November-January was entirely skipped. Ordinarily the 

 lowest water stage of the year is in October, following the so-called long dry season. 

 But in Februan,-, when we were there, the river captains and crews on both the 

 Demernra and Essequibo Rivers reported that the water there was the lowest they 

 had ever seen it at any season. Swamps which I made some effort to reach, and which 

 I was assured I would find waist deep in water, were in every case entirely dry, and 

 usually baked and cracked. * * * I believe the time of year to go after both of 

 these groups (Tipulidie and SjTphidoe) in the Tropics is August or the end of the long 

 rainy season. The end of the short rainy sea.son (December and JanuarjO would ;ilso 

 be favorable, but this is an uncertain season and has failed in the past, as it did in 

 1911-12. In fact, the best time for collecting in either Trinidad or BritLsh Guiana 

 is during your simimer vacation — .Tune, July, and August. It is rather strange that 

 more students in the East, close to New York, do not go South during the summer.* 



Chapada.—\ small village of Matto Gro-sso, Brazil, about 2-') miles ENE. of Cuyaba 

 (the capital of Matto Grosso), on the plateau. The \-illage itself is about 2,500 feet 

 above sea level, or 1,800 feet above Cuyaba, but collections are from all the surrounding 

 r^on as low as 1,.jO0 feet. This is a country of mixed forest and campo, or grassland, 

 with scattered trees; there are many streams — some small lakes or ponds and tracts 

 of more or less boggy savanna where the streams rise. The name Chapada is really a 

 generic application, applied to the plateau in general. The real name of this village 



^inta Anna la Chapada, and in some maps it api>ear.s as Santa Anna, but in all that 

 n it is known simply as Chapada, or the Chapada. 



"rumba. — A town on the River Paraguay, near the junction of the Taguary, the 

 port of entry for Matto Grosso. There is a tract of dry rocky land, a kind of island, in 

 the flood plain of the Paraguay, which is here very extensive. Collections were made 

 principally on the flood plain; the waters were rising, but I used to wade about with 



: oy pushing a canoe through the grass behind me. These flood plains are mostly 

 u grassland, with some forest along the river and channels.' (H. H. Smith.) 



: rem Among the Indians ot Guiana, by EverarU F. Iin Thum. (1883). 

 ! • tterfrom E. B. Williamson to J. O. Needham, April 23, 1912. 



. i om Contributions to a Knowledge of the Odonata of the Neotropical Region, by P. P. Calvert, Ann. 

 !■ gle Mils., vol. 6, No. 1, 1909. 



