188 UNITED STATES NATIONAL MUSEUM BULLETIN 276 



specimens, but the data on all of these specimens is questionable, or 

 they have been reared from egg masses found on imported nursery 

 stock. 



The most interesting of these specimens are the more than 70 M. 

 neustrium in the Illinois Natural History Survey Collection. They bear 

 accession numbers indicating they were collected from three different 

 localities in 1909. One collection was reared from larvae collected on 

 apple leaves 24 April at New Burnside, Johnson County, 111. by C. E. 

 Sanborn. The second was reared from eggs found on rose at Chicago 

 on 22 March by C. E. Sanborn. The third was reared from eggs found 

 on mountain ash at Princeton, Bureau County, III., on 6 February by 

 C. E. Sanborn. It is conceivable that all three collections could have 

 come from imported nursery stock since they were all collected in the 

 same year, but highly unlikely since the three localities are widely 

 separated and three different hosts are involved. If the data are not 

 suspect then it is possible that M. neustrium is established in the Midwest 

 since neustrium tents and adults superficially resemble those of M. 

 americanum and would most certainly not be regarded as different or 

 unusual. 



The following brief descriptions and diagnoses are included to make 

 it easier to identify these species if they are found in North America, 

 and to compare them with the North American species. 



All three of these Palearctic species build large tents similar to those 

 consti-ucted by M. americanum, M. californicum, and M. incurvum, and 

 all three feed on a wide variety of hosts, as do all of the Nearctic species 

 except M. tigris and M. constrictum which are restricted to oaks. They 

 are widely distributed in Europe, and at least one of them {neustrium) 

 occurs throughout the Palearctic from England to Japan. The egg 

 masses of all three apparently are laid as a helical band completely 

 encircling small twigs or stems similar to the way disstria, tigris, and 

 constrictum lay their eggs. The eggs are held in place by dark brown 

 spumaline which may also thinly cover the eggs, but apparently the 

 eggs are not covered with a thick layer of spumaline containing many 

 bubbles as are the egg masses of all North American species except 

 tigris. The spumaline of two egg masses of neustrium from Korea which 

 have been examined did not contain any specks. The cocoons of all 

 three species apparently are similar to those constructed by the North 

 American species, and are dusted with a yellowish powder. 



Larvae of all three species have color patterns different from any of 

 the North American species, but they, too, show much variation. All 

 three usually have a nearly continuous, narrow, middorsal whitish or 

 bluish-white stripe which will immediately separate them from all 

 North American species except americanum and a few rare individuals 



