360 
Psyche 
[September-December 
eggs groom more often than other females (Waldorf, 1974b), I 
expected males depositing spermatophores to exhibit a higher rate 
of grooming. 
Methods 
Mass cultures of Sinella coeca were maintained as previously 
described (Waldorf, 1971). Animals were held at room tempera- 
ture (25-26°C) in constant light. Brewer’s yeast was provided as 
food and replaced as the supply became contaminated with fungal 
growth. 
Ten pharate males were isolated in individual plastic-capped glass 
vials. The vials with an inner diameter of 22.0 mm contained a 
moist plaster of paris-charcoal substrate and food. Each male was 
observed for five minutes every 12 hours for 10 days. With the 
observor wearing a fiber mask to reduce disturbance of the animals, 
observations were begun 12 hours after isolation. Records were made 
of number of bouts of antennal grooming, total number of bouts of 
grooming and total seconds grooming. For the latter an electric 
second counter was activated by a depression switch. In addition, 
exuvia were removed and their presence recorded, and observations 
of spermatophore deposition behavior were noted. 
Table 1. The lengths of reproductive and nonreproductive instars 
in male Sinella coeca in days at 25-26°C. 
Reproductive Nonreproductive 
instar instar 
Instar length 5.4 3.1 
SD 1.006 .512 
No. of males 10 9 
Results 
Spermatophore deposition behaviors occur in Sinella coeca only in 
alternate instars. The lengths of the two types of instar (Table 1) 
differ significantly (t = 6.62, df 17; P < .005). The reproductive 
instars average 5.4 days, one and Y times the length of the non- 
reproductive ones. 
The percentages of the males exhibiting spermatophore deposition 
behavior through the reproductive instar appear in figure 1. The 
maximum occurred early in the instar with all males depositing 
spermatophores spontaneously 24-36 hours after ecdysis. There is a 
