332 



to the detriment of the tree. On the other hand, as soon as the tree 

 dies from being girdled the tissue becomes dry, offers more resistance 

 to burrowing and is of Uttle nutritive value to the larvae, which may 

 die. The pupal stage lasts about 10 days, and it seems that the insect 

 in Minnesota normally pupates during the latter part of May and 

 emerges from the cell about the middle of June. Two parasites were 

 noticed : One reared from the larvae, being a species of Atanycolus, 

 the other from an egg, belonging to the Trichogrammatidae. 



The cutting and burning of infested trees before the emergence of 

 the adults in the spring is an effective means of control. This should 

 not be neglected in the hope that the infested tree will recover the 

 next spring. As other methods seemed imperative, the trunks and 

 large limbs of some trees were sprayed during the past season with an 

 iron-sulphate and lime-sulphur mixture, while others were sprayed with 

 a Bordeaux mixture. This was done as a preventive measure during 

 the egg-laying season, and it seemed successful, as no beetles were 

 seen on the sprayed trees, even though they had been covered with 

 them the day previous to this treatment. In contrast with this, beetles 

 were seen in great numbers throughout the season on the unsprayed 

 trees near by. Other experiments are being made. 



Back (E. A.) & Pemberton (C. E.). Susceptibility of Citrous Fruits to 

 the Attack of the Mediterranean Fruit Fly. — Jl. Agric. Research, 

 Washington, D.C., iii, no. 4, January 1915, pp. 311-330, 3 figs. 

 3 plates. 



Data secured in the Hawaiian Islands tend to show that even if 

 Ceratitis eapitata, Wied. (the Mediterranean fruit fly) should obtain a 

 foothold in the warmer portions of the United States, it probably would 

 not be the serious pest to citrus fruits that previously published litera- 

 ture would indicate. These fruits are not' the favoured hosts of the 

 fly that the earlier writers thought. They may become quite badly 

 infested with well-grown larvae if allowed to remain on the tree long 

 after they become sufficiently ripe for the market, but larvae are seldom 

 found in their pulp until they are much over-ripe. In Honolulu, where 

 conditions are very favourable to early infestation, owing to the excessive 

 number of flies breeding in a profusion of non-citrus fruits, it is doubtful 

 whether grape-fruit, oranges, and lemons would ever become infested 

 until long after becoming over-ripe if the female fly formed a fresh 

 egg cavity for each batch of eggs deposited, for the reason that many of 

 the eggs and the young larvae found in the egg cavity and in the rag 

 of the rind would be killed by the oil of the cells ruptured in the 

 formation of the egg cavities, while of those larvae which succeed in 

 entering the rag, only a very small number are able to reach the pulp 

 because of the imperviousness of the rag. It is only the persistent 

 attack of successive lots of larvae, hatching from different batches of 

 eggs laid in the same puncture in which the oil has become inoperative, 

 that finally breaks down the barrier between the young larvae and 

 the pulp. Growers in California and Florida are admirably protected 

 from attack by the scarcity of wild host fruits that cannot be destroyed. 

 It will be found a practical undertaking there to remove such a number 

 of non-citrus host plants at present growing near citrus orchards that 

 the succession of fruits in which C. capiiata can breed during the large 



