'PORTO RICO EXPERIMENT STATION. 457 



parasites. Tii order of abundance, the orange scales observed were as 

 follows:" 



(1) The purple scale {]\fytilas pis citricola). — This is probably' the 

 most abundant and widely occurring orange scale on the island. 

 When numerous, especially on young trees, it does much harm. For- 

 tunately, it is heavily parasitized by a minute hymenopterous insect 

 and by at least three parasitic fungi. The hjanenopter alone nmst be 

 very eti'ective in keeping down the numbers of the scale, since on many 

 of the trees more than three-fourths of the mature scales were bored 

 by the escaping parasite. Of the fungus parasite, one was the well- 

 known red-scale fungus, Sp>hxrostUhe cocvopliilK. This occurs some- 

 what widely, but at the time of ni}' visit, the close of the dry season, 

 it was nowhere abundant. It pr()])ably spreads rapidl}^ with the )>egin- 

 ning of the rains, and is doubtless a factor of importance in keeping 

 down this and other scales. This fungus can be easilj^ cultivated in- 

 the laboratory,'' and in moist weather the cultures mixed with water 

 can be successfully used as a spray for introducing the fungus on trees 

 where it does not occur naturally. Another widely occurring fungus 

 forms a l)lack coating over the scales. The individual l)lack masses are 

 small and rounded, 1 to 2 millimeters in diameter, 1)ut they are crowded 

 together and often somewhat confluent over consideral)le areas when 

 the scales are abundant enough to form an incrustation. At lirst 

 these black masses are sessile, ])ut at length some of them are more or 

 less stalked and become <}uite hard. In most of the material secured 

 no spores are present and the systematic; position of the fungus remains 

 in doubt. There can be no question of its parasitic nature, since at 

 tirst it is confined exclusivel}' to the s(;ales and can be lifted away 

 with them. The fungus seems to grow leather slowh", but when the 

 scales are abundant it eventually destroys them over large areas. 

 The trunks and lim])s of man\' of the old trees on the island are black- 

 ened ))y the remains of this fungus. Some crude attempts at securing 

 artiticial cultures were made, but so far without success. What was 

 probably this same black fungus was sent to the writer some years ago 

 by Prof. W. M. Scott, State entomologist of (Jeorgia, on San Jose 

 scale from the southern part oi^ that State.'" There is a fragment of 

 what seems to be the same fungus in the P^Uis iierbarium on orange 

 twigs fromUmtitilla, Fla., collected by C. A. Hopkins, and sent to Mr. 

 Ellis ])y ]Miss E. A. Southworth, then of the United States Department 

 of Agriculture. The specimen is accompanied by notes aad drawings by 



«For the (k'tenninatioii of tliene scales and much other assistance I am indebted 

 to Prof. (). AV. Barrett, eiilomolof^ist of tlie Porto Kico Experiment Station. 



''Rolfs, Florida Sta. Bui. 41, 1897, pp. 527-531. 



*■ Professor Scott i)nl»lislied an account of the jiood work done by this funpue in 

 destroying the San Jose scale in I'roc. Georgia State Hort. See, 22 (1898), pp. 69, 70. 



