OF WASHINGTON, VOLUME XVIII, 1916 211 



the small, brown species, Tabanus bicolor, \Vied., is usually taken 

 in sweeping marshy places. Hine (Tabanidae of Ohio, page 48) 

 mentions this fact and states that "It has not been observed 

 annoying stock." Tabanus ohioensis, Hine, is usually taken in 

 similar situations. Both of these species have delicate wings 

 and are evidently weak fliers. Mr. Walton's personal copy of 

 Osten Sacken's Prodrome which is supposed to have come from 

 his library, contains the following manuscript note: Tabanus 

 psammophilus, O.S., "a strictly maritime species and probably 

 never attacking warm-blooded animals/' quoted from E. Schwarz, 

 Entomologica americana, Vol. 1, page 109. 



ANTS PROTECTING ACACIA TREES IN CENTRAL AMERICA. 



BY E. A. SCHWARZ. 



A recent paper by E. Wasmann in Tijdschrift voor Entomologie, 

 Vol. 58, 1915, which deals mainly with the ants of the genus 

 Pseudomyrma living in the thorns of the "Bull's-horn Thorn" 

 Acacias in Mexico and Central America, quotes fully the remark- 

 ably accurate account of these ants given by Thomas Belt in his 

 intensely interesting book "The Naturalist in Nicaragua." From 

 his own experience in the Canal Zone of Panama and at Tampico, 

 Mexico, the writer can fully corroborate the original observa- 

 tions of Mr. Belt to the effect that the ants effectually defend 

 the acacia trees against the attacks of man, cattle, and insects. 

 No leaf-eating caterpillars, no aphids, nor coccids are seen on 

 the trees; no leaf-cufting ants ever defoliate the same. But 

 there is one coleopteron, a Bruchus, which frequents the flowers 

 to oviposit and develops in the pods of the acacia without being 

 molested by the ants in any of its stages. 



At. Tampico a dead acacia was found in the midst of a row of 

 healthy trees. The dead tree had lost its leaves and the ants 

 had deserted it. It had the appearance of having been killed 

 by an insect larva boring in the roots and it would seem that the 

 ants are powerless to protect their host plant against the attack 

 of an underground enemy. However, efforts to pull out ront> 

 were not. successful. A few pieces of the trunk and larger branches 

 were broken off and carried to Washington, where in the course 

 of time the following Coleoptem were bred in addition to the 

 usual number of Hymenoptera parasites: Seven species of Ceram- 

 bycidae (one cerambycinc and six lamiids); one Imprestid (Agril- 

 us); and four species of predaceous beetles (one Bothrideres, 

 one Lathropus, one Trogosita, and one Clerus). 



