571 



The adult emerged from the cocoon in about 15 days, and lived in 

 breeding cages for three or four days. The number of Aphids eaten 

 per diem by the larva varied from 24 to 27. The temperature under 

 which the experiments were conducted varied during the day between 

 60° and 80° F. and during the night between 40° and 50° V. The life- 

 cycle under these conditions required an average period of 38 days. 



BoRDEX (A.D.). The Mouth-parts of the Thysanopteraandthe Relation 

 of Thrips to the non-setting of certain Fruits and Seeds. — Jl. Econ. 

 Enlom., Concord, viii, no. o, June 1915, pp. 354-360, 1 plate. 



The mouth-parts of the Thysanoptera are adapted for sucking and 

 their food probably consists entirely of plant juices. Observations 

 were made by the author on Heliothrips haemorrhoidalis, Partheno- 

 thrips dracenae, Taeniofhrips (Euthrips) pyri (pear thrips), FranJdiniella 

 (E.) tritici and E. occidentaUs. The feeding habits of the young were 

 found to be similar to those of the adult. A detailed description of 

 the mouth-parts is given. On deciduous fruits the thrips feed on the 

 tender floral parts with very serious results to the setting of the fruit. 

 The injured tissues turn brown and later black, often resulting in 

 premature falling of the flower. When thrips occur in numbers, early- 

 flowering almonds are only slightly damaged, but later flowering prunes, 

 peaches, etc., are severely injured. In the Santa Clara Valley, peach 

 orchards are commonly infested by T. pyri, E. occidentaUs, F. tritici, 

 and Aeolothrips kuwanai. F. tritici and E. occidentaUs have been 

 collected from lucerne ; the young floral parts are attacked, causing 

 the premature falling of the flower or young seed-pod. 



Leonard (M. D.). Further Experiments in the Control of the Tarnished 

 Plant-Bug {Lygus pratensis, Linn.). — Jl. Econ. Entom., Concord, 

 viii, no. 3, June 1915, pp, 361-367. 



To test the efficiency of a fence in excluding Lygus j^ratensis from 

 nurseries, wire screen cloth 6 feet wide was used to enclose an area 

 470 feet by 240 feet ; this area contained peach trees and was sur- 

 rounded on three sides by peaches and on the fourth by ornamenta 

 trees. The soil was banked up 3 or 4 inches at the base in order to 

 prevent any insects from crawling through open spaces at the bottom 

 caused by irregularities in the ground . It had been previously observed 

 that although the plant- bugs did not actually fly over the fence, from 

 the surrounding weeds, they would fly on to the fence, crawl to the 

 top and then fly into the enclosure. To prevent this, a strip of tangle- 

 foot about 4 inches wide was placed along the upper edge of the wire 

 cloth. Counts were made regularly of the number of bugs found 

 within the enclosure and of the number of injured terminals of the 

 trees . By 2 9th July , about 75 per cent . of the trees i nside th e enclo.sure 

 were injured and counting was discontinued. On 8th November, 

 about 95 per cent, were injured. By comparison with a control plot 

 it was found that the fence excluded many bugs, but from the final 

 condition of the trees not enough had been kept out to render its use 

 practicable. Very few of the bugs alighted on the fence higher than 

 6 feet from the ground, and after crawling to the edge of the tanglefoot, 



