248 EXPERIMENT STATION RECORD. 



the Southern States, however, it probably does winter as viviparous females, 

 since viviparous forms are not uncommon at Clemson College, S. C, in Decem- 

 ber, whereas a careful search for sexual individuals proved fruitless. "As is 

 characteristic of this tribe of plant lice (Callipterini), the species under discus- 

 sion is sporadic in habit and is very easily roused, the least disturbance causing 

 it to jump from its host. This habit is much to its advantage, for it seems to 

 render the si>ecies almost immune from predaceous and parasitic enemies." 



In generation studies at La Fayette, Ind., in 1913, the details of which are 

 reported in tabular form, the author has found the maximum number to be 17 

 «nd the minimum 8; thus 12i is the approximate average number of genera- 

 tions. The first generation extended over a period of 39 days, from April 22 

 to May 31 ; the second, 60 days ; the third, 54 days, etc. ; and the eighth genera- 

 tion, which includes the last generation of the last-born series, being the longest, 

 extending over a period of 128 days. Studies by Phillips and Parks of the line 

 of generations of C trifolii from May 13, 1909, to oviparous generation, at La 

 Fayette, Ind., are also presented in tabular from. Observations indicate that 

 this species invariably molts but four times. 



"Weather conditions, esi^ecially heavy rains, are thought to be the most im- 

 portant checks of the yellow clover-aphis. The aphis fungus, Empusa aphidis, 

 is likewise quite an imix)rtant factor in holding this plant louse in check. On 

 account of its habits of living singly and jumping from the leaf at the least 

 disturbance, this species is seldom attacked by internal parasites. Three species 

 of coccinellids. namely. McgiUa maculata, Hippodamia convergens, and Cocci- 

 nella 9-notaia, have been reared from larvae found feeding on C. trifolii. 



A bibliography of 14 titles is appended. 



The conquest of verruga, C. H. T. Townsend (Peru To-day, 6 (1914), No. 2, 

 pp. 57-67, figs. 20). — This is a brief statement of the results of investigations 

 relating to the transmission of verruga by biting flies {Phlebotomus verruca- 

 rum), carried on under the direction of the author from February 22, 1913, to 

 June, 1914, accounts relating to which have been previously noted (E. S. R.. 20, 

 p. 856; 30, pp. 252, 658; 31, p. S47). 



The author believes it to be possible to I'emove entii'ely the Phlebotomus from 

 the vicinity of any given habitation or house in the verruga zone, by simply 

 clearing away all stone walls and rock piles within a radius of several hundred 

 yards and doing away with any caves or cavities in the rock that may be 

 located within that radius. 



Contribution to the knowledge of the biology of Bibio hortulanus and its 

 control, E. Molz and W. Pietsch (Ztschr. Wiss. Insektenbiol., 10 (1914), Nos. 

 3, pp. 98-105; Jf, pp. 121-125; ahs. in Internal. Inst. Agr. [Rome], Mo. Bui. 

 Ag'r. Intel, and; Plant Diseases, 5 (1914), ^"o. 7, pp. 966, 967). — ^An outbreak of 

 B. hortulanus occurred in the Province of Saxony in 1913 and in addition to 

 sugar beets, the only crop which it had previously been known to injure, it 

 attacked spring barley and wheat so severely that many fields had to be plowed 

 up and resown. The damage is caused by the larvae, which feed until the begin- 

 ning of May and then pupate at from 2 to 4 in. below the surface of the soil. 



In investigations conducted by the author it was found that contact poisons 

 had very little effect. The most satisfactory control measures consist in plow- 

 ing deeply and rolling at the time of pupation. 



The apple root borer, F. E. Brooks (U. S. Dcpt. Agr., Jour. Agr. Research, 

 3 (1914), No. 2, pp. 179-188, pis. 3). — During the course of investigations of 

 the rouudheaded apple-tree borer (Saperda Candida) carried oo by the author 

 in West Virginia in 1911, numerous associated buri'ows of a smaller insect were 

 observed which later wei*e found to be those of Agrilus rittaticollis, a beetle 

 which hitherto had not been recognized as an enemy of cultivated fruit trees, 



