404 



A. melanoscelus hibernates as a third-stage larva within the cocoon. 

 The majority of adults emerge when the hatching of the eggs of 

 P. dispar is at its maximum, usually during the second week in May. 

 Reproduction is frequently parthenogenetic. The act of oviposition 

 is described. The adults emerging from the hibernating generation 

 generally parasitise the first- and second-stage larvae and even the 

 third should they be present ; but the next generation of adults,, 

 although chiefly parasitising the third stage, will occasionally attempt 

 to oviposit on the fifth- and sixth-stage larvae, though they are usually 

 prevented from doing so by the long hairs present in these stages. 

 The largest number of eggs obtained from one female was 535, but 

 under natural conditions the number is probably about 1,000. 



The egg stage lasts from 48-72 hours, according to the temperature. 

 There are three larval stages. The length of these is slightly longer 

 in the summer than in the spring generation. Pupation occurs in a 

 cocoon external to the host and lasts from 5 to 9 days ; the pupae 

 may be found singly or in clusters either on the foliage or on the debris 

 on the ground, as well as on the trunk and small branches. Those 

 of the second generation are scattered over the trunk and in clusters, 

 under the larger limbs. They are generally not abundant until about 

 the second week in July. 



The introduction and establishment of this parasite into New 

 England are discussed, and the methods of colonisation and distri- 

 bution are described. The imported parasites were first thought to 

 belong to several species, but it now appears that the adults liberated 

 in June 1911 at North Saugus, Massachusetts, from cocoons imported 

 from Sicily as A. solitariiis, belonged to the first generation of ^4. 

 melanoscelus, whereas those received later were of the second generation 

 of this species. About 17,000 cocoons were received in July and 

 August 1911, each one of which was placed in a gelatin capsule and 

 allowed to pass the winter under outdoor conditions. All parasites, 

 liberated since 1913 have been put out while in the cocoon and have 

 been of the summer-issuing generation, most of the colonies containing 

 500 cocoons. The cocoons are placed in small cylindrical covered 

 cans, which are nailed to the tree in inconspicuous places. The adults 

 e.scape through three j in. holes punched in the can near the top. Tree- 

 banding material must be placed right round the can to prevent ants. 

 from destroying the colony. Woodland areas with a light to medium 

 gipsy moth infestation are preferable for the liberation of these parasites,, 

 and heavily infested areas should be avoided. Owing to the rapid 

 dispersal of the parasite one colony was placed in each town and 

 several large areas have thus become well stocked. Parasites have 

 been recovered from all but one of the colonies liberated before 1918,. 

 from half of those put out in 1918 and from both liberated in 1919. 

 Late in the summer of 1920 the parasites were recovered from towns, 

 colonised in June of that year. 



Thorne (G.) & GiDDiNGs (L. A.). The Sugar-beet Nematode in the 



Western States. — U.S. Dept. Agric, Washington, D.C., Farmers' 

 Bull. 1248, February 1922, 16 pp., 10 figs. 



Heterodera schachtii, Schmidt, is found in many of the principal beet- 

 growing sections of Utah, Idaho, California and Colorado. The results 

 of recent surveys show that the infestation is spreading rapidly in 

 some localities. The life-history, causes of spread and remedial 

 measures are discussed [R.A.E., A, viii, 414]. The most common 



