June, 1914] Alexander: Craneflies From Costa Rica. 120 



Mcsonotal prxscutum grayish brown, the psiudosutural fovc-c prominent, 

 elongate, reddish brown ; scutum, scutcUum, postnotum and pleura: grayish 

 brown. Halteres rather long, uniform light yellow. Legs, cons and trochanters 

 yellowish brown, femora and tibia; similar, the tips of the individual segments 

 not infuscatcd, tarsi brown. Wings rather uniform light yellow, the veins pale. 

 Venation as in fig. 4. 



.•\bdonien brown. Hypopygium about as in other species of the genus 

 except the ventral appendage (see fig. 0) which here is long and slender, 

 chitinized heavily, and having its inner or cephalic margin provided with a long 

 dense brush of hairs. The anal lobe is provided with a dense covering of long 

 pale hairs. 



Female, similar but larger. 



Holotype, male, Alajucla, C. R., alt. 3,100 ft., Sept. 15, '09 (Dr. 

 P. P. Calvert). 



Allotype, female, with the type. 



Types in the collection Acad. Nat. Sci. Phil. 



The numerous species of Molophiliis bear a great superficial re- 

 semblance to one another and most of the species can only be sep- 

 arated by a comparative study of the male genitalia. The ventral 

 apical appendage is heavily chitinized and very various in shape in 

 the diflferent species and offers the best criterion for specific determi- 

 nation. The only other Central American Molophiliis described is 

 M. guatemalensis Alexander' which I have figured in Entomological 

 News, Vol. XXY, pi. 9, fig. 3, 1914; as shown by the figure, the 

 ventral appendages of the two species are entirely different. 



Genus ERIOPTERA Meigen. 

 Subgenus Mesocyphona Osten Sacken. 

 Erioptera (Mesocyphona) parva Osten Sacken. 



Two males and two females from Alajucla, C. R., Sept. 15, '09. 

 Erioptera (Mesocyphona) caloptera femoranigra .-MeNander. 



Many specimens of both sexes, including the type material, from 

 Juan Vinas, C. R., July 21, '09; they were attracted to a light on a 

 rainy evening. Also from Cache, C. R., near the Rio Reventazon alt. 

 3.450 ft., Mar. 4, '10, and at Alajuela, C. R., alt., 3,100 ft., Sept. 15, 

 '09, one female specimen. Eleven specimens from the type locality 

 now before me have the dark bands on the femora much paler and 

 less intense, but undoubtedly belong here. 



1 Proc. U. S. Xat. Mus., Vol. 44, p. 511, 1913. 



