340 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



Jamaica in company with Neohlattella eurydice and N eohlattella dryas. 

 They also Hst most of the associations cited by Hebard (1917). 



Ramme (1923) reported that he found in Germany four species of 

 Ectobius (lapponicus, hicidus, pallidus, and Sylvester) living together 

 in an area about 50 m. by 200 m. Although he had stated that his 

 specimens of E. lucidus were a distinct species in 1923, Ramme 

 (1951) later decided that they were a form of E. Sylvester, E. Syl- 

 vester f, lucidus. 



Dow (1955) reported trapping Blattella gennanica, Periplaneta 

 americana, and Periplaneta hrunnea in houses and privies in south 

 Texas. At our request Dr. Dow (personal communication, 1958) 

 analyzed his records to determine whether there were indications of 

 associations between these species, with the following results : 



As stated in my published note, the roaches were at first classified to genus 

 only. The 83 Periplaneta subsequently identified to species represented 28 differ- 

 ent collections, 11 from houses and 17 from privies, all in Pharr, Texas. Tabu- 

 lation of the data shows first that P. americana was taken only once in a house 

 and that P. hrunnea was taken only 4 times in privies. Of course this distribution 

 greatly reduces the probability that they would be caught together, and it is not 

 surprising that P. americana was trapped alone in the single house collection. 

 P. brimnea, however, was trapped with P. americana 2 of the 4 times it 

 occurred in privy collections. 



To investigate the occurrence of Periplaneta with and without Blattella, an 

 analysis has been made of 560 trap collections taken in 40 houses and 40 as- 

 sociated privies in Pharr, Texas, in weekly intervals (from May 14 to June 22 

 [1948]). In the houses, Periplaneta and Blattella were caught in the same jar 

 26 times, Periplaneta alone 12 times, Blattella alone 83 times, and neither 

 genus 159 times. In a fourfold table, the value of chi-square (14.7) is significant 

 and indicates that the frequencies are not proportional. The number of times 

 Periplaneta and Blattella actually occurred together (26) is, however, much 

 larger than the expected number calculated from the row and column frequencies 

 (14.8). In the privies, Periplaneta and Blattella were caught in the same jar 

 9 times, Periplaneta alone 50 times, Blattella alone 18 times, and neither genus 

 203 times. In a fourfold table, the value of chi-square (1.95) is not significant 

 but the same type of disproportion is evident and the expected frequency of both 

 genera in one trap is 5.7, lower than the actual frequency of 9. Both immature 

 and adult roaches are included in this analysis. 



The above evidence would be more satisfactory if based on more extensive 

 data. There is also a possible objection in that the traps were operated for at 

 least overnight, during which time one species could theoretically supplant 

 another. Of course, it is doubtful that there is anything involved here like terri- 

 tory (in the ornithologists' sense). On the other hand, it is well to consider 

 that Periplaneta and Blattella are both likely to be more abundant in the same 

 type of favorable location and that this factor might offset in part some direct 

 antagonism between the species. 



The only known specimen of Ischnoptera podoces was captured in 

 company with the type series of Cariblatta nebulicola, in dead leaf 



