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SiMANTON (F. L.). The Terrapin Scale : an Important Insect Enemy 

 of Peach Orchards. — U. S. Dept. Agric, Washington, B.C., Bull, 

 no. 351, 22nd April 1916, 96 pp., 19 figs., 3 plates, 44 tables. 

 [Received 24th August 1916.] 



Eulecanium nigrofasciatu7n, Perg., is confined to the eastern parts of 

 the United States, being especially abundant in Pennsylvania and 

 Maryland. In Canada, it has been found on maple in Ontario. About 

 30 kinds of plants are attacked, the most important of which, arranged 

 in order of preference, are peach, plum, maple, cherry, sycamore and 

 mistletoe. There is one generation annually, the winter being passed 

 in the immature female stage. Activity is resumed in spring, maturity 

 being reached during June, when reproduction begins. The reproductive 

 period continues for about a month, but in some instances may be 

 prolonged for 3| months. Young emerging from the parent scale 

 migrate to the leaves. About six weeks later, young females pass to 

 the twigs, whither they are followed after a week by the males. After 

 pairing, the females grow rapidly for two or three weeks ; activity then 

 gradually diminishes until the insects pass into the dormant winter 

 state. The date at which hibernation ends is determined by weather 

 conditions. Experiments conducted at Mont Alto, Pennsylvania, 

 showed that in 1913 activity was resumed about 1st April. Growth 

 was rapid for a month, then proceeded more slowly. All females under 

 observation reached maturity by 10th June, A vigorous female may 

 give rise to as many as 900 young. The time spent after birth within 

 the brood chamber varied from one to three days. In 1912, the first 

 young appeared in the brood chamber on 6th June and began to 

 emerge on 8th June ; emergence ceased by 17th July. More extended 

 observations made in 1915 showed that the rate of emergence reached 

 a maximum five days after the beginning of migration and then rapidly 

 declined. Migration took place between 10 a.m. and 3 p.m, of each 

 day, migrating larvae being able to live for two or three days without 

 food. Dispersal during the migratory period may be effected : — 

 (1) by the dropping of larvae from dead branches, fruit, etc. ; (2) by 

 wind ; (3) by rain ; (4) by other insects, birds, labourers, etc. 

 Mortality at this time was found to be very small and only 15 out of 

 12,336 larvae were unsuccessful in finding attachment to the underside 

 of leaves. The first instar was completed in from 16 to 17 days in July 

 1913 and in 25 days in August 1912, A certain amount of dispersal 

 may probably occur during this time, since larvae on detached, drjTng 

 leaves are able to move on to living fohage. The second instar, passed 

 on the leaves, lasted for 18 days under favourable conditions. 

 Migration to the twigs during the third instar began about 1st August, 

 reached a maximum before the middle of the month, then continued 

 gradually until the falHng of the leaves. Passage took place during 

 the hottest part of the day, i.e., between about 12.30 p.m, and 3 p.m, 

 and ceased almost entirely below 70° F. Larvae which failed to become 

 attached to the twigs were unable to survive for more than three days. 

 It is probable that passage from one tree to another cannot be effected 

 unless the branches of the two are actually in contact. The final 

 position taken up was found to be on the twigs, preferably on the basal 

 part of the young growth, though many became attached to older 

 Wood. The maximum quantity of honeydew was secreted during the 



