18S JOURNAL, BOMBAY NATURAL HISTORY SOCIETY. 



it may be useful to notice the fun^i, Isaria destructor, Mets., and Isaria opkio- 

 glossoides, Kras., which are stated by Kiinckel d'Herculais to have caused the total 

 destruction of the eggs of the migratory locust Pachytylus migratorius, over large 

 areas in South Russian in 1884, when the fungus was investigated and artificially 

 cultivated by two Russian naturalists Metschnikoff and Krassilstchick. In this 

 connection, it should be observed that great care is necessary in investigating the 

 subject of zymotic diseases amongst insects ; vegetable organisms found in the 

 tissues of dead insects being sometimes of purely post mortem origin. 



With regard to the parasites and insectivoious animals, which are supposed to 

 account fer much of the mortality amongst locusts in India, little has been 

 ascertained ; but the observations made on locusts in other parts of the world leave 

 small doubt as to the nature of the numerous agencies that are at work. In the 

 United States, according to Riley, the Rocky Mountain locust {Caloptenus spretus) 

 is largely kept down by insectivorous animals and parasites, some of the most 

 effective of which are themselves insects. Riley found that besides being devoured 

 by vertebrate animals, such as pigs, poultry and other birds, toads, frogs, snakes, 

 &c, and by the larger predaceous insects, snch as Carabid and Cicindelid beetles, 

 Asilid flies, some species of Scutelleridae (soldier bugs), and Mantitla?, the eggs of 

 the locusts, are parasitized by a Dipterous insect {Anthomyia angustifrons), which 

 is estimated to destroy as much as 10 per cent, of them, by a little scarlet mite, 

 and by an Ichneumon fly ; while, after the locust emerges from the egg, it is 

 parasitized by a mite (Astoma grylluria), w hich attaches itself to its body and sucks 

 its juices, and by various Tachinidae and Ichueumonidae, whose grubs develop in 

 its tissues and thereby cause its death. Stoll observed that the locust (Acridium 

 peregrinum) in Central America, was much infested by a parasitic Mermis (hair 

 worm), which was present in six out of the ten specimens he dissected. While 

 Kiinckel d'Herculais states that in Russia it has been observed that Nematode 

 worms pierce the locust egg cases and penetrate into the eggs which they destroy. 

 In India little has been recorded beyond the fact that in the Bombay invasion of 

 1882-83 kites and crows fed upon the locusts, and that the presence was observed 

 of two species of parasites, viz., "small red parasites," which were observed 

 clinging to the bodies of the locusts, and which are likely to have been mites, 

 allied to the Astoma gryllaria of America, and a " hair worm," which was report- 

 ed to kill the locusts, no further particulars about it however being given, though 

 it would seem likely to be a Nematode, allied to those observed in Russia and 

 Central America. 



E. C. COTES, 

 The 2}st February 1890. Indian Museum, Calcutta. 



A MANUAL OF FORESTRY.* 



Professor Schlich's new Manual of Forestry will probably form the standard 

 work for the instruction of Indian Forest Officers. In the interest of science, 



* Thie letter appeared in the Bombay Gazette on the 20th March 1890. 



