200 abstracts: entomology 



ing any of these species are grouped together as recurrent Tropidoleptus 

 zones, considering Tropidoleptus to be the most characteristic form. 



The importance of the investigation lies chiefly in its disclosures in 

 regard to the ancient geography of the region. Both the departure 

 and the return of the fauna must have been due to diastrophic changes 

 that at one time brought about conditions unfavorable to the continued 

 existence of the fauna and at another time not only restored favorable 

 conditions but also provided means for the remigration of the fauna 

 into the region. Such changes may have resulted (1) from the alter- 

 nate closing and reopening of an actual passageway which alternately 

 prevented and permitted the access of the fauna and of waters favorable 

 to them, or (2) from changes that affected the direction, character, or 

 volume of existing ocean currents. David White. 



ENTOMOLOGY .—Observations on the life history of Micromalthus 



debilis Lee. H. S. Barber. Proceedings of the Entomological 



Society of Washington 15: 31-38, pis. 2 and 3. April 9, 1913. 



The few records and captures of this supposedly rare beetle from the 



original capture of adult and larva in 1874 are given, together with a 



preliminary account of the author's attempts to breed adults from larvae 



found in the vicinity of Washington. These attempts demonstrate 'an 



involved paedogenetic reproduction (the first case known among the 



beetles) through three types of larvae, but the development of the sexed 



adults is still unknown to the writer. Comparison is made with other 



examples of unusual reproduction. The systematic position of the species 



is considered doubtful. J. C. Crawford. 



ENTOMOLOGY. — The dispersion of the gypsy moth. A. F. Burgess. 

 Bureau of Entomology Bulletin 119:1-62, pis. 1-16. 1913. 

 The present paper is an extended account of the spread of this species, 

 Porthetria dispar, as observed principally in Massachusetts. The char- 

 acter of its spread is divided into two groups, local and long-distance 

 spread; the former due to the transportation of caterpillars or egg clus- 

 ters on carriages or wagons moving a short distance, or of egg clusters on 

 driftwood; the latter due to shipment of egg clusters on lumber products, 

 nursery stock, or boxes from the infested territory to outside points. 

 Caterpillars may also be carried long distances on automobiles or trolley 

 cars, and colonies have actually been established at a great distance 

 from the mother colony by such means. The greatest factor in ready 

 dispersion is that the first stage caterpillars are carried by winds. Ex- 

 tensive experiments were carried on to prove this, traps being moored 

 in ponds or lakes, or put on tops of towers of various sorts in order to 



